I think the fact that he _doesnt_ have a lot of synergy with ancestors or his signature crew means that he is highly
adaptive and can support most crews very well be it TT or Ressers. Hes kind of like an all rounder support master now.
Reliquary is a pretty darn good upgrade though. At first I was underwhelmed as well but the Ancestors are
all very solid units. Most experienced players would agree that its no easy task to take down any of
them once let alone twice.
For retainer I think its more so he can bring Komainu into a Resser list but the Brace ability on the
Ashigaru is not something to overlook. Also Onryo give out Adversary which gives spirits positive attack flips.
Both Komainu and the Ashi get their suits from any Ancestors presence, not just Yan. Komainu with the burning trigger
built in hit pretty hard for a 5 pt model.
I agree Fury of the Yomi isnt amazing for TT, probably more suited for Ressers with plenty of spirit options, and even then
it would be a very situational action, but potentially game changing in the right circumstance.
Heres an example of how I'd use his upgrades.
Vs. a casting heavy opponent, Ascend to Ash, giving him Impossible to wound.
Vs. a melee/shooty crew, Spirit, giving him Incorpreal.
Vs. a weenie crew with a lot of weak units bunched up, Bone ascendant.
Using your excess chi for giving your units +2 Armor and making them spirits.
If you don't like the theme of his crew though I'd suggest finding something you will have more fun with playing and painting.
I, like many others, chose his crew pretty much all based on the theme and asthetics of the crew.