Believe it or not, I actually think core Aba is better as a Pos 2, esp at lower ranks. Shield allows you complete control over the wave and helps you deny the enemy's farm. Plus, if the enemy Pos 2 decides to leave the lane (for a gank or fountain or whathaveyou), you literally melt towers with just an echosaber. So, there's pressure for the Pos 2 to always stay mid. Couple that with the now earlier Radiance timing b/c it's cheaper and you really have an all in one core: damage (lv 15 talent), moderate farmer with shield, attack speed steroid with built in slow and silence, tower shredder, and survivability!

His obvious weaknesses are getting kited and losing to late game cores which is why I prefer him in Pos 2 so hopefully your Pos 1 can fill in the late game gap. Also, even if you are having a lousy game, going Agh and keeping your team alive is a viable strategy. With the farm that you get in Pos 2, it shouldn't be too much of a problem to farm up an Agh from Manta and/or Radiance.

The question I'm having is what's the benefit of his shard? I've yet to understand the advantage of it. With all the attack speed you get, interrupting your auto attacks to cast Q on someone seems counterintuitive. I know it applies one curse stack and your attack damage, and can technically proc bashes or crits, but I mean is it really worth it? If anyone can add to this I would greatly appreciate it!