Thanks for all the comments. My speakers are multiple feet away from both the back and side walls. I have also toed them in toward my seating position. Have also tried crossing them in front of seating position, I don't like that as much.
Sounds here like you may have already done the setup and experimentation that can make the difference between a hifi and a really good musical system. If you are satisfied that the speaker placement is as good as you can get it, it may well be time to look into component upgrades.
Now by my math given your room and your speakers, 60 watts in a tube amp should give you plenty of power. Tubes are well-known for improved imaging, smoother and more detailed sound. But you should consider that what a tube brings to an amplifier, it also brings to a preamplifier. If OTOH the preamp is loosing detail for any reason, there is nothing you can do to recover it downstream no matter the amp or speaker. So you might want to consider a tube preamp first rather than the amplifier.
Naturally while a tube preamp can bring a lot of benefit, if you are driving a solid state amp I don't think you will hear everything its doing. But at least it will let you know if you are heading in the right direction, and tube preamps are much less service oriented IMO/IME.
Of course if it were me I would consider both. I just like tube equipment better :)