We need exposure for success and high volume exchanges like bittrex and poloniex certainly helps.
My opinion is on the assumption that we already have a great dev team !
Yes we do. But how does exposure help them developing the software?
Exposure make more people aware of the coin, more people want to get a slice of it, the price goes up and it certainly brings more investors/developers/etc to the coin.And the existing devs also gets motivated as they see their work is recognised and rewarded by the public, which boost the productivity even further.