I do not see any of your mentioned *issues* in the current version of Unity…
“higher cost”
-> Unity has been free for a long time now, even longer than Corona. Only a few features are restricted to Unity PRO but you can easily add similar functionality to your projects by yourself. What exactly do you mean by “higher cost”. No one forces you to create the next AAA-3D Game with Unity (which would result in higher cost :P)
“more time populating the world”
-> I guess it´s hard to drag and drop an object, a sprite for example, from a folder into the scene?
“felt like wrking against the system”
-> Unity 4.3 has added native 2D support a few months ago(!). Now it is as easy as 3D but you can always extend your 2D game with 3D features.
regarding your last point
-> When did you use Unity for the last time? There are two versions, free and Pro.
I am using the free version at the moment because I do not need any Pro features yet. There is no need for extended draw-call optimization - I have done this by smart coding and level optimizations by myself. There is no need for Sprite Atlases (Pro feature) since I am using third party software like TexturePacker. I can release my projects to all platforms for free except for the new consoles because they need special licenses by Sony/Microsoft/etc.
There is still the Unity splash screen at the beginning of your project but if you are done with your game and want to release it, just subscribe to Unity Pro! They have switched their licensing stuff to a monthly basis which is around 75$ per month.If this is too much at the beginning then just release it with the free version!