So far my targ deckbuilding experience has been:
Fealty: hits maybe 4 cards, also in faction card draw sucks, can't use plaza because very few dudes are actually good at power challenges
Splashing elsewhere: kinda fixes lacking icons, card draw still sucks
Splashing targ: illyrio, jorah, unsullied, then the rest kinda sucks. (dothraki dork and a dragon I guess?)
They don't have anything besides characters to splash though, which can be an issue.
Tyrell, Bara and Greyjoy seem to be the big dogs, NW and Lannister not too far behind
Fealty seems bad outside of NW just due to how few loyal cards are in the game. NW can at least play a crow every turn off it, which is a decent draw engine, most other factions can trigger it maybe every other turn, not worth all the deckbuilding restrictions.