The city doesn't have the funds to build out LRT's instead of bus routes. If they did, they would have done it. You make do with what you have.
As for your ring route suggestion, it's a nice fantasy, but the ring road itself is over 100km long(when completed). Our current total system length is 60km. How much ridership is there on an outer ring route, compared to what you get going downtown? I'd suggest not much.
There are some good suggestions for fantasy routes here.
http://forum.skyscraperpage.com/showthread.php?t=218185