Well, it's down to a matter of opinion. I say Chopper's fights will still be "Oh no, I have to finish this opponent in three minutes" and you say they'll be "Oh no, I have to finish this opponent in three minutes because after that I may be tempted to take two more Rumble Balls and turn into a monster". No point in discussing it further, is there?
However, I could point out that Chopper's fighting abilities were put in question when he had to resort to Monster Point. Not because he's weak (he isn't, and I've enjoyed all of his fights a lot) but because it showed his immense dependence on the Rumble Ball, once the time limit was over his confidence faltered.
Id love to stop, but one thing about this bugs me. Chopper isn't "temped" to take the rumble ball, he's forced to otherwise his enemy will kill him. I'm pretty sure he doesn't want to use the monster form, he wants to finish his enemies with his normal rumble ball attacks. So, if Chopper wants to stop this monster from coming out then he needs to get stronger.
Breaking away from Monkeyspirit, I'm getting a little tired of everyone talking about Chopper's rumble balls as a dependancy. What, it's a completely inferior method of fighting just because it has an obvious weakness? I really just feel that it's more of a "weakness in their fighting style" that all the SHs have in some way.
–Zoro is a weaker fighter without 3 swords. Without them he can only beat much, much weaker fighters.
--Sanji will never use his hands.
--Nami is worthless in fighting without her tact.
--Robin can't beat someone who doesn't have bones to break, or is difficult to reach around.
--Usopp's attacks are generally weak until he can get creative.
--Franky has a cola limit, and a back problem.
..and Luffy..well he's covered his weakeness pretty well I think. Aside from the obvious DF stuff.
So really, I'd like to think of as a limit in his fighting style, and not a "dependancy." Think about the SHs weaknesses and compare. Every fighter "needs" something outside of themselves to be strong.