First, I'll compliment the changes so far - the ship is loads better than it was in 4.86, and has a clearly defined playstyle different than the Ranseur, and deserves to see more play than it did in the previous release. It's even got advantages for the first time in its history; 360 secondary turrets in slots 8-9 that allow me to put a pair of flak in any direction except straight down and a tremendous broadside that is actually a bit more powerful (not to mention more accurate) than Ranseur's, to name two. The fifth primary was a great addition.
That being said, the ship still seems too large for its stats. Size comparisons in-game still has it being just a bit smaller than the Valor from the sides, and is maybe 90-95% the length. Sarissa is fast, but still can't evade fire like a Dunkirk, which the ship feels modeled after (and is certainly comparable to in armor/core).
Dunkirk is a med bs while Sarissa is a heavy one. It's more comparable to Valor in everything except hp and arcs. Treat it as a middle ground between Dunkirk (run of the mill med bs) and Valor (only the RM bs is heavier)