The thing about Morgana mid is that she's a one trick pony. One way to engage, one way to disengage, one way to farm. Shes well rounded in all those ways, the trick is to get her out of that window of always having something to even things out. Let's tackle her tormented ground first: this will most likely be maxed first and her main farming tool, by mid game it will clear the whole wave, how do you make her use it somewhere else other than to just delete a whole wave? well any more sets one under a snared opponent, and almost as many will still use it if they THINK their q was going to hit, so what I do is i play on the sides of the lane, bush warded ifc, but the point is to bait her q first and foremost, but also looking to get her to waste her DoT/AoE damage. If you do this successfully, she is on CD for a ten second window or so, this is the time you use to trade back or safely farm your wave. As far as her black shield goes, how hard she is to catch depends on the player, I often find myself playing ahri against morg mid, what I do is run toward her aggressively like im about to force a trade and then just auto or throw a q her way. If she falls for it, she just used a valuable spell shield for nothing and now leaves me a 15 second window to engage on her with little no no resistance.
So... it's not that Morgana mid is brainless, though I understand what you mean, I had to stop supporting with her because it just became the same boring stuff game after game, but Morgana gets into a routine when in a solo lane setting, and the only way to have meaningful trades with her is to make her use her abilities in a way that brings a stop to her farm/poke cycle and to do it often enough to keep her from healing through that damage on the next wave.
Hope that helps a bit, sorry for the wall.