If Kishi was a better artist. Studio Pierrot would have had a better quality.
That was a senseless point. Kishi has a great simple style that actually translates to animation more easily.
OT: It can't physically happen. To give a series that's as long as Naruto consistently great animation is... impossible. Any animation studio would find themselves bankrupt long before the series is even done. Think of any greatly animated series and you'll find it won't even touch 200 eps, never mind 300 or 400.
Honestly, this series is well animated considering the length. People ought to be thankful for how much Pierrot already do invest in the series. So what if a few episodes really hit low, it's not bad overall and there are whole action episodes done by some of Japan's finest - that's not done by any comparable series.