From making this squad:
Aspas
Zekken
N4rrate
Bang
JohnQT
sentinels have gotten really comfortable playing single duelist comps, and it works... ok for them. i think the pivot to double duelist comps would benefit them, but also aspas is not the one to help them. zekken and aspas both play a lot of jett and neon, and generally double duelist comps in this meta incorporate yoru, which neither of them are that comfortable on.
also, yes, zellsis is a bit of a weak link in terms of stats, but there is value to keeping him. leaving a roster as is breeds familiarity which helps comfortability, and zellsis is the biggest presence on stage, he's a vibe merchant. he's very passionate, but it helps in the fact that he can very easily get the team in the right headspace to build momentum
TL;DR: sentinels don't play double duelist, aspas is not a good pickup for them, changing their roster could be very bad