speakers in older amps

[Irish Pennant]

I have an old Genz Benz Shenandoah 85 amp. I'm also not very knowledgeable in the sound producing industry.

Just curious if speaker technology has evolved much over the last 30 years? Has it kept pace with the evolution of the acoustic guitar pickups? and is there a speaker type that is specific to acoustic guitar?

When looking for speaker replacement, what is it that one looks for in order to make an upgrade?

With an 85wt amp, do you upgrade to a speaker that has a higher wattage, such as a 100 or 150 watt, if so, why?

Is there a tradeoff between wanting more warmth or a fuller sound spectrum? and are speaker types this specific?

Thanks in advance for any and all replies.