No, they aren't in the least top-heavy- at least the small blocks like the V7 series. I have a V7ii Stornello, a 744cc Scrambler-ish variant of the V7ii family. It's a good-to-great handling bike, not especially heavy at well under 500 lbs with a full 5.5. gallon tank. It isn't going to challenge any middleweight hoon bike in the straights or, frankly through the curves on the stock tires. But it won't give up much in the curves and a good rider can pretty easily outcorner a passable rider on a better performing bike.
It has a few shortcomings. It runs both cylinders through a single throttle body and for whatever reason the breed is known for being slow to warm up. Even here in Florida it requires 3-4 minutes to come to a point where it doesn't threaten to stall even sitting at idle. After that it, idles fine and there are no further peculiar fueling issues. Also, getting parts is a pain in the [censored]. It runs on 10w-60 oil, has an OEM-only filter cartridge, and the tire sizes are odd, limiting the range of replacements.
On the plus side, gauges are big except for the digital info at the bottom, riding position is very neutral and the stock seat is comfortable. The bike makes almost all the torque you're going to get by 2800 RPMs, and from a stop to 80 mph it's a blast to ride. Bigger than average fuel tank is a nice thing to have. Quality of finish and spec is good. I put Ohlins on mine in the back, but haven't seen the need yet to rework the front suspension, basic as it is. Brembo brakes are good enough. Paint and finish work is outstanding.
Would I buy it again? Probably not. Not that I'm disappointed in the bike, but the dealer/parts thing is a concern along with some of the foibles mentioned above. If I were considering this bike when Yamaha's XSR700 was out, I'm pretty sure I'd have gotten the XSR. As it stands I have other bikes to scratch different itches, so I'm content. And the MG gets a fair bit of attention for what that's worth.