Yes, if you are creative enough, you can do a lot with channeling only one element. On the other hand, if you have a GM that is equally creative, he will still compel the hell out of you. Or you might just get more opportunities to self compel, either way, you'll end up with a pile of fate points.
I see that being true for ritual vs. thaumaturgy as well. Granted, some specialisations are better for some things than others, but that is equally true for channeling different elements.
Both channeling and ritual will leave blind spots in your arsenal in comparison to their more expensive counterparts. You can minimize but not eliminate those blindspots by creative use, but it is eliminated by buying the full power. I see them both pretty much en par.