The Yamahas have a bit of a reputation for brightness and less emphasis on the low end.
Bigger speakers theoretically have greater latitude for better sound, but in actual practice, most speakers of about 4" and above can be good enough subject to your needs and preferences. Imo, the big “problem” with A/B testing a 5" side-by-side with a 7" is that the 5" is invariably bound to sound like it is lacking next to the 7". If you were to listen to the 5" on its own however, you would probably find that it is actually quite adequate. That said though, for ideal dynamic range, 5" speakers should be used with a sub, but sub configuration can be challenging. With speakers 6.5" and above, subs become optional depending on how low you want to go. That’s why in my previous post I suggested at least 6.5" speakers if you’re not using a sub. However in a bedroom, you may be restricted to 5" speakers, but they can be more than good enough.
I know because I face this dilemma myself, also for use in my bedroom. When I listen to these speakers side-by-side, I like the T7Vs the best (I listen mostly to bass-heavy music), but they are simply too big for both ideal and practical placement in my room. When I am ready to pick up a pair, I will in all likelihood get 5.25" speakers, and I am certain from listening to them that within my bedroom, on its own, where I am NOT comparing it next to 7" speakers, it provides plenty enough low-end for me to enjoy even the heavier tunes that I listen to the most.