The mcu's are the way to go, and from what I've seen you've been getting plenty of support from forum members up the steep learning curve of mcu's. Persevere - I think you and I are in the same place on mcu's- and as long as you commit to it, success is inevitable. I think it's obvious to the majority of forum members here that you have plenty of enthusiasm for the field of robotics. So you didn't get it the first time, so what? Keep your energy up and try again. You can't throw your arms up in despair over any obstacle, no matter how large or small. Aim for success, but be prepared to fail - it's an inevitable part of doing anything. My first PIC's are in the mail, and I'm planning on at least getting my head around some simple programming between now and the end of summer. There was this cheezy movie once with Anthony Hopkins and one of the Baldwin brothers, but I remembered a line Hopkins used that went (I'm probably paraphrasing), "What one man can do, any man can do." I told you what I'm going to do - what makes what you can do any different?
That said, what are your reasons for excluding the sensors you've mentioned?