I think that for bigger guys road bikes can be really disappointing at first. I actually rode a lot less after I got mine. If you have a lot of belly weight and flexibility issues it can be hard to find advantages to riding a road bike. For me it's been difficult. 6 months before I could properly wrap my hands over and around the hoods, 9 months before I started using "the big gear".
I lost a little weight this week. This morning I decided to ride my bike to a nice bike path that runs the Han river in Seoul Korea. I only lost like 3lbs but when I was riding to Seoul I discovered that it was just enough to comfortably ride in the drops for the first time ever. So for the first time I felt what all the aerodynamic hype is about. My back isn't used to it so I can only hold it for like 5-10 minutes at a time but it made such a big difference. I had no idea how much faster you could ride hunched over like that. I wore my body out sprinting and trying to draft, I'm in so much pain but very happy about today