Getting a VC investment is just like a marriage except for the things being equal part. Typically all the power comes with those preferred shares and the only real way to "get a divorce" is to buy them off just like the founder did.
There really are only 3 true options if you need to raise large amounts of institutional capital. 1) Stage a round with so many VCs that if you get one or more bad ones, they get shouted down by the other ones 2) Just take investments from people you know for certain are great (hard to do unless you've taken money from them before 3) Only take a very small amount so you don't actually give up control. That's harder to do since most vc's won't do the deal otherwise.
Hmmm, yeah ... it's possible that these VCs only accepted a non-control position because they were desperate due to their fund closing fairly soon (let's assume within 2-3 or so years) and needing another chance at a big hit.
There really are only 3 true options if you need to raise large amounts of institutional capital. 1) Stage a round with so many VCs that if you get one or more bad ones, they get shouted down by the other ones 2) Just take investments from people you know for certain are great (hard to do unless you've taken money from them before 3) Only take a very small amount so you don't actually give up control. That's harder to do since most vc's won't do the deal otherwise.