IMHO, flabby bass is not dependent on power output. IF everything except power output are the same you'd still have flabby bass. With the 50wt'er you might have less bass, on the level of 4 to 5 db, but not tighter bass. And the 50 wt'er might be smoother.
Two amps, one pure class A, other A/B
Here is the question.
You have two amps from the same manufacturer, they have the same power supply, the same transformers, most likely the same output transistors.
One is biased as pure class A and outputs 50W.
The other is biased as class A/B and outputs 150W.
If 50W amp clearly cannot drive your speakers (you have flabby bass), will the 150W one do the better job, considering the only difference is bias?
You have two amps from the same manufacturer, they have the same power supply, the same transformers, most likely the same output transistors.
One is biased as pure class A and outputs 50W.
The other is biased as class A/B and outputs 150W.
If 50W amp clearly cannot drive your speakers (you have flabby bass), will the 150W one do the better job, considering the only difference is bias?