i For one, hope the SAO and Accel World never merge. i heard speculations / roamors that it's the direction the SAO manga is heading in.
I've watched both animes and give the Accel world manga try but i must say Accel world is totally shit in my opinion
AW and SAO's source materials are both Light Novels, not mangas (Those are also separate adaptations, and in AW's case it even died like its anime). Also, you can rest assured on that, while at first it seemed at least that AW was the "future" of SAO, the latest volumes in AW and SAO's new arc post-Alicization confirmed the opposite, more or less: Accel World seems to be an 'alternative future' of SAO's timeline, at the very least, where things went wildly different at least when it comes to Alicization's ending, but at the very least it did confirm it's not meant to be a direct sequel/future of it. AW is more than likely one of the many possible 'what ifs' futures of an SAO timeline, but not of the Canon one.
But to be Honest it seems there is a problem with SAO is the story still good or there something wrong with it I know guy who fan of it said he hate Alicezation but that was his opinion I never seen it
Alicezation got me back into it. Honestly after the first half of season 1 its never been all that great. Alicezation has Kiritto become a vegetable for a while, and it starts with him not remembering he is kirito, so maybe one of those things was upsetting fro your friend.
Alicization is quite ambivalent to some because while it's without a doubt the best-written part of SAO is also the longest and darkest in many aspects, so opinions on it can be quite split in many ways (Never helped by the people who think nothing after Aincrad was ever quite as good, which I personally disagree with as ironically Aincrad is the arc that I enjoy the least of the whole Canon timeline...and also the one the author insists the most in going back to expand with spin-offs and sidestories, lol). It's generally accepted as SAO's best part, though, if one can stomach all the suffering and brutality (Especially in the novels, the anime ironically censored a lot of the most gory parts).