If you like the bike with the exception of the shifters, I'll bet you'll get used to it in time. Just this past weekend, I went from a Trek 7100, also with the grip shifters, to a Trek Pilot with the not-grip shifters (I don't know what they're called
). Going to the shifting on my new bike has been an adjustment, too. I took a 15 mile ride tonight and purposely changed gears a lot, and it's already starting to feel natural.
About the weight of the bike -- if the 7300 is the same weight as the 7100, I'll agree that the bike is heavy and clunky. I didn't think so until I started test-riding some lighter bikes. The tires on the 7100 were 35mm, my new bike has 28mm tires. The LBS recommended to DH that he switch to 28mm tires on his 7100 to get a little more speed. So, the LBS thinks narrower tires will make a difference. His bike is still there, so we don't yet know if the narrower tires will make much of a difference.
Hope this helped and hope you find a good solution.
"I learned what every dreaming child needs to know - no horizon is so far that you cannot see above or beyond it." -- Beryl Markham, Aviation Pioneer