Well the idea that the Midichlorians are "sentient" is an opinion presented by Qui-Gon Jinn, the rogue Jedi who always seems to be disagreeing with the majority of the Jedi Council. When Qui-Gon talks to Yoda about how he thinks Anakin could be the chosen one, Yoda responds with something to the effect of "revealed your opinion is". I think it's quite possible that while Qui-Gon pictures the Midichlorians in little hats playing poker, the rest of the council and possibly a majority of the Jedi Order sees them as merely the antenna through which all living things can tune into the Force.

Sure there's nothing to prove this theory, but there's nothing to disprove it either.

At the end of the day, it all comes down to how you prefer to look at it. If you want to see the Midichlorian concept as a limiter, you can do that, I just don't undertsand why you would want to when you obviousy would prefer it wasn't a limiter.