Sometimes, in discussion forums, the hair-splitting gets rather silly. Other times - and this is one - it seems everyone focuses on the "mote" and misses the 'beam."

As far as this thread is concerned, there is absolutely nothing wrong with the panel; and the brand of manufacture is irrelevant trivia.

The switch was hot, and the breaker didn't trip? So? 20 amps will make a lot of heat. Just look at any toaster, hair dryer, or space heater. We have no reason to infer that the breaker was not operating properly.

Nor was there any sort of 'short circuit.'

What did exist was a high resistance connection. This could have been everything from a loose wire to a switch wearing out from old age. Perhaps the cause was the aluminum wiring; or. perhaps, the switch was not approved for use with aluminum wire. Or, again, just ordinary wear and tear.

If it was simply an old switch, the replacing the panel and completely re-wiring the house will not make the slightest difference in the temperature of the switch.

I'm also assuming this was an ordinary switch; a heavily loaded dimmer switch can feel 'hot' in normal operation. ("hot" and "warm" being rather subjective terms}.