Changing the compatibility mode for all sites in one go is as simple as switching general.useragent.compatMode.firefox to "true". But BE WARNED about that option, since it will fix one side of the internet and break the other side.
I also think you are exaggerating when you say it has now become "Firefox without add-ons". That's not even remotely true and I do take offense to that statement.
Most extensions still work out of the box. The ones that don't we are working on. Another chunk of add-ons will return to functioning status in 25.0.1 that fixes an important Jetpack issue.
So yes, this situation will change and will improve. As some would say "no matter how you look at it, any divorce is painful".
A few points in detail:
User387 wrote:Sure you can say "It's their fault!" for not developing(more like tweaking) addons and sites for your browser especially,
We don't ask this.
As far as sites go, Pale Moon is fully capable of rendering them and if it worked in 24.7, then it will work the exact same way in 25.0, if it wasn't for the fact that the websites in question use a
deprecated, naive method of trying to find out features by looking specifically at named browsers, called "user agent sniffing". This is a
bad idea, really,
it is (even
Mozilla says so!) and the current Pale Moon issues with these sites are the clearest demonstration of exactly how bad an idea it is to do useragent sniffing as a website instead of doing proper feature and capability detection.
As far as add-ons go, add-ons that no longer work are, with the sole exception the SDK bug that will be fixed in 25.0.1, add-ons that very specifically limit themselves to target applications. Normally this kind of targeting isn't even needed unless you want to cater to multiple target applications with different requirements in one universal package. Add-ons that do target a specific application while it's not needed are being specifically restrictive towards
any truly independent browser based on the same rendering engine.
User387 wrote:PM addons page already looks like Sleipnir addons one(dead and empty), and there is not much hope for other extensions being ported.
On the contrary, the add-ons site is brand new and more extensions are added each day it is up. Why is it brand new? because before now, there was no pressing need for it.
User387 wrote:Wish everything could stay as it was
Maintaining the status quo would be a slow death for Pale Moon and a fade into oblivion. It's not an option.