You know, I MIGHT actually consider playing a bit if we had the old client back. I know they were really banking on the Playstation release to bring in players, but all it did was drive away the PC players who enjoyed the old one.
I know for a fact that if they brought back the old client we would see 100's of players online again. Just for that nostalgic feeling- Look at OSRS.
I tried getting used to the new client, but it frustrated me into quitting out before I ever could acclimate to it. I'd throw down some pox on the old client, though, if it were an option.