Well, yes and no. Yes, his experience would make him valuable (and probably a major factor in the church being willing to take him back), but you'd also have to wonder just how much experience actually counts for with Hunters. A lot of Hunters were also soldiers (like Victor and Moira), bandits or huntsmen before becoming Hunters, meaning that they aren't exactly new at fighting and killing, though they may be so at facing beasts, superhuman opponents and being superhuman themselves. I imagine Raine would be much more likely to identify weaknesses than most, though.
It's also worth noting that in Bloodborne, the deadliest of all Hunters (usually) ends up being the player character, besting even hundred-year veterans like Gehrman... and that the player character has been a Hunter for only one night. Sure, they might have died a lot learning those things, but they were able to keep at it no matter how much they died until they learned. Compared to Raine, who only has one life, that's a much more intense way of learning.
In other words, I wouldn't expect Moira (a former Paleblood Hunter) to be impressed.