It was thought that BIP9 would be a faster and safer way of doing softforks than the Satoshi-style method, but boy did that turn out to be wrong. It was definitely not intended to be a way of letting miners "vote"; miners are not and should not be a decision-making body for Bitcoin.
TBF, BIP 9 is very similar to the method used in previous soft forks, namely that miners signal readiness via a different version number and that the rules activate when the signalling passes a certain threshold. This had worked for several soft forks in the past, so it didn't seem like that bad of an idea. BIP 9 just made this method more sane by not having to burn version numbers and to allow for simultaneous soft forks.