A lot better? In case you think so, then I'd say you don't give the team a lot of credit. He will be a help, yes. He will contribute with much more than Von Wafer does so far, clearly. However, to expect a lot from West is in my opinion rather delusional.
Don't get me wrong, I love Delonte. The first jersey I ever bought was with Delonte, and I still sport it as often as I can. He's easily in my top 5 favourite players in the league. So it's not because I have a bias against him, quite the contrary!
However, think of what was thought with the Marquis Daniels, Jermaine O'Neal and Nate Robinson additions. I at least had higher expectations that what they have shown in their Celtic careers right now (looking at an 'average' basis - I am quite aware that espec. Nate has been very big for us in the playoffs). I would be pleasantly surprised if Delonte did not in some way emulate what they have done. Some good, some bad - but not a revelation, nothing significant - and nothing that is going to make us a lot better.