As an SY player I would say King of Beggars suffers from few stackable tribute units.
There are a lot of high tribute cost units, however King of Beggars would require more units like Renegade Mage and higher provision ones at that.
Let us go over all its targets in detail:
Tinboy: Completely overpriced and paying tribute 7 or 8 is not making much of a difference on the last play
Professor: More situational on the Tribute and not one one would usually plan on using.
Whoreson Senior: It requires swarming and focusing on Crimes has actually more DJ synergy than KB synergy.
Madame Luiza: "Anti-Synergy" with KB, given that the large juicy Tributes cost 0 with her, with or without KB.
Savolla: Again the same issue as Tinboy, also this unit majorly relies on the Luiza combo to reach the usually mentioned "op-level".
Moreelse: Again not a Tribute one plans on using, it is worth it with Luiza, if one misses more important targets or if the target has at the very least 10 points, reducing the cost does not make the Tribute any more or less usable.
Graden/Tamara Strenger: Witch Hunters have more DJ synergy, given that DJ generates a more variable amount of coins and using Crimes helps getting enough coins to pay for them (also Tamara is bad).
Azar Javed: A decent KB card, although there are not many engines KB decks tend to want to protect that badly and a lot of SY decks cut Javed in either case.
Adriano: Another large cost Tribute card, given that one usually cannot pay for too many of these the passive from KB has no way of stacking too much on these (and most of them want to have Luiza support, further reducing the bonus of KB).
Sir Skewertooth: A completely Intimidate focused card and thus Crime focused and that means DJ (also it is bad).
Arena Ghoul: With the KB bonus this is a 6 for 5, which is pretty bad and for the best case undesirable.
Firesworn Scribe: No synergy and not even 1 for 1 coins into points, even on KB.
Keeper of the Flame: KB decks do not tend to swarm and rowstack enough to warrant using this.
Renegade Mage: A 3 point body with 3 removal, very decent for 4 provisions (one of the only cards to abuse KB).
Fence: An unit with very high ceiling (in the dream scenario a 12 for 4), that can easily reach up to 8-10 for 4p and 2 coins.
The problem is that coin stacking is not something that comes without downsides and playing that much into tall punish, as well as having to keep all those coins necessary for interactions for a 4p is not enough on its own to justify KB.
Blindeye Apothecary: Noone plays this, the reason should be fairly clear with little synergy within SY (outside of maybe Whoreson's Freakshow).
To summarize:
King of Beggars has 2 actually decent bronze units synergizing with it, however 1 requires a lot of setup (Fence) and the other is a 6 for 4p.
The few actual synergies with Gold cards are not enough to actually use KB over DJ.
The advantage DJ has over KB is that DJ can gain a lot of coins from multiple Crimes and unlike Tributes those Crimes do not require previous coin generation.
The answer should be to give KB more decent bronze Tribute cards, if KB can get as many additional coins (by spending less than usually required) as DJ through Crimes KB would be as good.
