After playing an MP unfair comp stomp last night, I got to thinking..  While I'm pretty confident in my ability to expand early-game (significantly faster than the AI and faster than most players I've seen) and know how to wreak havoc late-game with phase missiles, Kosturas, Orky assault deployment, Ruiners, etc, I'm not as confident in my mid-game.

For example, in the game I played last night, I expanded faster than my TEC human ally (actually, about twice as fast) in a linear path with an Evacuator, scooping up every planet in my path, heading straight for the enemy worlds.  When I got there, I immediately began to expand sideways until I hit a pirate base which I knew would keep the enemy out until late-game.  By doing so, I had effectively blocked off about a third of the map for my own use (I would have done more, but I wanted to leave my ally with a decent amount of worlds).  I proceeded to capture an enemy planet in the way of my sideways expansion on the way.  Now what?

Yes, I had just claimed a large chunk of the map, so I naturally began capturing it with a second fleet let by a Skirantra and focused more on strike craft and flak than my main (which was about 80% assailants) while my Evacuator and it's fleet guarded the border worlds while Orkies were contructed where necessary.  Eventually, I was #1 in both empire and economy across all subcategories.  In fleet, I was dead last, though first in defenses.

Eventually, I had accrued enough ships and research in the late-game, that I went on the attack, and facing an Advent adversary, wasn't difficult to win.

My question then is is there anything else I could do during mid-game?  

Also, I know I always have a tiny fleet, not even thinking of purchasing the first fleet increase research until mid-game, at which point I do for the sake of creating a second fleet.  In late-game, I'll just mass produce fleets and will typically research most of the fleet supply ones.  Is there anything necessarily wrong with having such a tiny fleet?  Players I've seen (and I know the AI does this) will purchase the next fleet capacity upgrade very rapidly, yet I don't bother attacking at this phase of the game so I don't even care how much they outnumber me.  Worse case scenario, I sick an Orky on them if they try to attack me.  I guess my strategy might be best described as follows...

EXPAND!!!!!!
tank
tank
tank
NUKE!

Vasari are certainly powerful late-game once all toys are unlocked and IMO seem to be able to expand faster than the rest, but suffer in the mid-game.  Is this just me or is it supposed to be like this, and in either case, what could I do that would be more productive?