I want to try analyze this objectively and sum up some of the arguments in this thread.
1) If he is played normaly, he can kill
a) an up to 8 strength unit and be killed afterwards by 7 points of removal.
b) an up to 5 strength unit and be killed afterwards by 9 points of removal.
c) nothing if the enemy has an unit with 11 strength or more
2) He is played by
i) Royal Command
ii) player has 2 Drakkars on the board.
2.1 Which both makes him 7 strength +2. This way he can either kill:
a) an up to 11 strength unit and be killed by 7 points of removal afterwards
b) an up to 9 strength unit and be killed by 9 points of removal
c) an up to 8 strength unit and be killed by 10 points of removal, such that he is out of Alzurs range
d) nothing if the enemy has a unit with 16 strength or more
3) He is boosted only by 1 point from a Drakar. This way he can either kill:
a) an up to 10 strength unit and be killed by 7 points of removal
b) an up to 7 strength unit and be killed by 9 points of removal
c) an up to 6 strength unit and be killed by 10 points of removal
d) nothing, if the enemy has at least an 11 strength unit
These are most of the situations happening after him being played.
3. So what can be done to counter him:
3.1 using Mandrake immediantly afterwards, which will directly kill him and make the enemy unable to revive him. This gives the Imlerith player an advantage of exactly the number of points that he removed. In most cases this will make this a trade a silver versus a gold and at least 5 points, which is worth for the Imlerith player. With Whisperess or Vesemir it can be slightly disadvantegous for the Imlerith player, but nonetheless, now the enemy has to run exactly those cards and sacrafice a silver and a gold card for it.
To sum this up, Mandrake isn't bad against Imlerith bad, isn't a card that works in every deck.
3.2 Playing an at least 11 strength unit beforehand. If Imlerith isn'T boosted this will kill him immediantly, and even if he is boosted, it will leave him at 7 points such easy to remove. Let's have a look at all cards that can achieve this, when played without much setup as it is the beginning of the round:
a) Neutral: Ciri Dash, Iris Companions, Saenthisessi Blaze, Sarah, Geralt, Ciri:Nova, Shupe, Villen
b) NR: Tridam Infantry, Redanian Knight, Redanian Elite, Dandelion, Ronvid, Trollolo, Ves
c) ST: Elias, Xavier, Saskia, card handbuffed to 11 strength
d) MO: Goliat, Cyclops, Fiend, Old Speartip Asleep, Imperial Manticore,
e) SK: Tuirsearch Skirmisher, Dimmun Pirate, Vabjorn, An Craite Warrior, Jutta, Hjalmar, Olaf, Raging Berserk, Wild Boar of the Sea
f) NG: Tibor, Assire, Master of Disguise, Guardian, Vattier, Knight, Xarthisius
I tried to mark all those units that I think of are more than memes currently and won't be used before round 3. While this is quite a big number, it definetly doesn't include cards for every archetype. And not even all of them make sense to use at the start of the round.
3.3 Removing him after his first attack:
a) by a card that deals more than 9 damage: Assasin, Assasination, Caellach +Assasin, Elf Blade, Harald, Leo Bonhardt, Lugos, Manticore Venom, Spear, Parasite, Viper Witcher, Seltkirk, Champion
b) by a card that deals 9 damage: Alzurs Thunder, + Ithlinne, +Dethmold, +Keira, +Ida, +Vaedemakar,
c) a card that deals 7 or 8 damage: Cursed Sorceress, Ioverth, Morenn, Panther, Rock Barrage, Serrit, Vandergrifts Blade, Vernon Roche,
I probably forgot a few units, but if it needs at least 9 damage to kill him, there aren't that many reliable cards left. It is either a version of Alzurs, or it is Assasin or Viper Witcher. None of the other cards sees currently much play, but at least Leo and Lugos shouldn't be that bad to include. Nonetheless this leaves most other decks with the condition to run an Alzur if they want to remove him. And while every deck should definetly carry at least 1 removal, at the same time, if this removal has to be a form of Alzurs , we have again an autoinclude card ( and I know that this is nearly the case in the current state of the game), which is bad gamedesign. It should be possible, to use softer removal as engines, who need 2 or 3 turns to kill something, as these are also a form of removal.
If the enemy doesn't manage to directly remove Imlerith, the dealt damage can be just nullified by using Mandrake to heal and strengthen Imlerith, so only half killing him directly doesn't really work either.
3.4 Scorching him:
a) directly: he already dealt at least 5 damage, so if directly scorched, the Imlerith player will have gained value
b) after 1 turn, when Mandrake was used: assuming only dealt 5 damage on the first time and 7 on the second, and the 7 strength bronze that was removed had an unremoved effect of 4 points, then it is a Bronze and a Silver against a Silver and Gold and +8 points, which is still worth it for the Imlerith player.
Furthermore, there are currently 3 different versions of Scorch with Villen and Gigni of which only the normal scorch will work. So in a lot of cases the enemy won't even have the correct scorch.
3.5 Locking him:
Most locks in their current state are that week that they aren't worth it against him:
a) D-Shackles: Imlerith needs only to kill a 3 power unit to be worth it
b) Margarita: he needs to kill a 5 power unit to be worth
c) Morvudd: needs to kill a 8 power unit to be worth it
d) Auckes: needs to kill a 6 power unit (if played with Drakkars, he needs to kill an 8 power unit)
e) Donar an Hindar: needs to kill a 7 power unit
f) Ciaran: needs to kill an 8 power unit
g) Radovid: needs to kill a 1 power unit, 5 power unit if Radovid had another target, +7 if that other target was a Drakkar
h) Letho+Regis assuming there was an 11 power unit next to Imlerith: Imlerith needs to kill an 8 power unit
So, from all of the locks I would only consider, Donar, Morvudd and Ciaran as viable against Imlerith. And Donar is useless in most other situations, and Ciaran everywhere outside movement.
4. Comparing Immlerith to other long time effects:
a) Yen Con and Triss But: both of them need quite a couple of time to get there full value and can therefore be easily removed over 2 or 3 turns.
b) bronze engines: bronze engines like Vrihedd Dragoon or Reinforced Trebuchet need at least 3 turns to get average value for a Bronze, which gives the enemy a lot more time.
To sum this up, Imlerith can easily be removed, but not that easy anymore if he was already boosted by 2, which shouldn't be that hard to accomplish. In that case, you either need to have played an 11 strength unit beforehand, which is only possible for a couple of archetypes and even then not always that good. As a lock, there is mainyl Morvudd for Monsters. Or you need Alzur or an even stronger removal, which forces most decks to run at least 2 of these, or they might be stuck in a case when they can't get it. Therefore this card has a s a single card a huge impact on the whole deckbuilding in an unhealthy way, as it forces a quite limited number of cards to be included in each deck.
The game includes multiple mechanics and a lot of possibilities to tech against them. So, every player should decide on his own, against what he wants to tech and against what he doesn't want to. And of course not teching against something should leave the player in a disadvantage, but it should never just cause an autodefeat. And moreover, there should be always a couple of possibilities to tech against something, so the player can include the one best suited for his deck. I don't see either of these point given for Imlerith.