The very best sounding amps I've heard are all low in output. But, these amps are not appropriate for many speakers and in situations where high volume is a requirement and/or the room is extremely large. So there is a minimum amount of power that is needed, and that minimum is situational.
It is hard to say whether the 50 watts you have is sufficient. All else being equal, more power will at least afford you more headroom for the brief peaks when playing very loudly. That may or may not be a sufficient basis to upgrade to higher power. But, often there is a sonic price to more power. I once heard a comparison between a 50 watt Rowland amp and a very similar Rowland amp that was much more powerful. I actually preferred the sound of the lower powered amp, and the speakers used in the comparison where supposedly a power/current hog. I don't know why this was the case--it could be that using a larger number of output transistors adversely affects the sound, it could be that some transistor amps don't sound as good when they are just loafing at a small fraction of their capability--but this showed me that more is not necessarily better.
All of my current amps are low-powered tube units (6.5 watts/channel being the brawniest), but, I have appropriately efficient speakers and I prize good low-volume performance over ability to shake the room.
It is hard to say whether the 50 watts you have is sufficient. All else being equal, more power will at least afford you more headroom for the brief peaks when playing very loudly. That may or may not be a sufficient basis to upgrade to higher power. But, often there is a sonic price to more power. I once heard a comparison between a 50 watt Rowland amp and a very similar Rowland amp that was much more powerful. I actually preferred the sound of the lower powered amp, and the speakers used in the comparison where supposedly a power/current hog. I don't know why this was the case--it could be that using a larger number of output transistors adversely affects the sound, it could be that some transistor amps don't sound as good when they are just loafing at a small fraction of their capability--but this showed me that more is not necessarily better.
All of my current amps are low-powered tube units (6.5 watts/channel being the brawniest), but, I have appropriately efficient speakers and I prize good low-volume performance over ability to shake the room.