I am not surprised at all. Pathetic leader ability. Of all the four leaders revealed, he is the most pathetic leader. Let me tell you why.
Traps are usually played to force the opponents out of a round and to get maximum use from them, usually they are triggered at the end of the round. If I am 6 points down, I will play Mahakam Horn. The opponent may think it is Pit Trap and pass and the trap gets triggered and I win the round and I pass. Usually, the traps are played and planned such that they are triggered at the round end and I pass.
Now, Eldain would need three traps already triggered for him to be useful. He has to draw three traps and use them (probably for a much less efficient time) to use his ability. The only trap which can be used early is Incinerating Trap and opponents can smell it miles away and make it less useless. Every other trap is kind of useful at the end of your round.
Lets not forget about artifact removal too. He could be the only leader - a leader- who can brick. How many traps should we have in our deck so that we can guarantee that he gets three targets and you can't wait till R3 because your R1 and R2 as he can't guarantee a targetable trap in R3. You may have to use him in R1 unnecessarily.
I was kind of expecting the leader to synergize with cards that want traps to be in board like Ioverth, Half-Elf Hunter, or Pyro technician.
Thanks CDPR for giving another Tier 4 or Tier 5 ST leader. After all what can I expect from you for ST other than a pathetic, useless junk leader?