Both of them regret the split in my opinion but Noel more than Liam. Liam has been his usual self assured self in front of the camera saying oasis will never reform and constantly having a dig at Noel and stuff along that sort of stuff but has mentioned it's a shame some oasis songs will never be played again so he must regret it as he had an easy time of it with massive stadium tours beging worshipped by many but now has to start again and cope with not being in the best band in the world and prove himself.

Noel as you have mentioned has hinted a lot at how much he loved being in oasis and his trepidation of venturing out as a front man, also he knows deep down he made the decision to quit far too hastily and knows if he had done the final 3 shows then he would still be the man at the side of the stage and not the one in the centre.

He's outright said that he regrets not doing those last gigs and continuing with his plan for a hiatus.

But he also said in the KROC interview somethig that I think sums up his opinion on the split

"It's a shame it had to end the way it did but, in hindsight, I think that everyone can agree that it was probably for the best."

I think he misses the idea of being in the band. But you can also tell that he got off on the buzz of finally being the sole arbiter of an album again. I think that he was tired and burnt out around 2000...but by the time he rediscovered the joy of making music again around the time of DBTT the band had already morphed into something else and I don't think he was truly happy with that but there was no way to turn it back.

I think part of the reason that he started getting so serious about the solo album concept, to the point that he was going to put Oasis on hiatus, was that he missed that level of tyranical control to a certain extent and the ability to say "I am writing all the songs for this album...I have a vision so everyone shut up and play what I tell them"