I am actually going to have to disagree. GPU mining means fpga's and asics can still function and thus dominate which is why YAC must be sure to keep it self safe from things such as this. Furthermore, GPU mining would only increase the difficulty and make my small supply of coins even smaller 
No but really litecoin isn't that well off, sure it is better than YAC or most other alt coins but thats pretty much because it was first not because GPU mining has treated it well.
If need be while it would be painful I think that the N factor should be increased if gpu mining became a viable option lest people begin the process of pumping and dumping. If we want YAC to last we need to keep it CPU only. Because even if everyone is going slower it will at least be a network wide slowdown and hit everyone relatively evenly which is partly why the massive speed decreases arent that bad because it is only a speed decrease for the network and not just for you and these decreases help keep YAC slightly safer with each increment. What I think we need next TBH is a proper mining program with stratum support. That way we can capitalize on the hashrate we still have left and get better feedback and less stale shares.