What do you think? There are many freeware titles that previously had been commercial titles? Should GOG try to acquire the rights to add them to the library?

https://en.wikipedia.org/wiki/List_of_commercial_video_games_released_as_freeware

At least for very popular games such as Castle of the Winds, Command & Conquer 1/2/RA, Enemy Nations, etc. this would be a tremendous addition to the GOG catalogue. But then of course it would also mean additional work since they would need to test the titles, possibly patch them for new systems, etc.

What do you think?

I think that if they are available as freeware there is not much need to have them here. Freeware titles can be shared via torrents already quite well.

On the other hand if they invest some money in order to make them fit and require the rights (and revoke the freeware status) and sell them for say a really small price - why not.

Sure, I'm all for Command and Conquer appearing here. Does EA want though?
Even if they do, is there any guarantee that we'll be able to just add them for free to our accounts or we'll have to buy them as part of the Ultimate Collection?

No.

Do you really want support to have another set of things to worry about? Really?

Well, I think a lot of people are willing to pay a bit if they get the guarantee that the game works without having to fiddle around. Maybe if they added those freeware titles for a small price it could work and convince the bigger studios as well. I think they currently do it for Ground Control already, although I would rather think about a price of 1 to 2 dollars.

And then there are titles that can easily be emulated (with DOSBox / ScummVM / etc.), there would be not much the support has to do.

If they add the freeware titles then they will not sell many when you can get them
somewhere else for zilch.

Definitely all for C&C 1,2 & RA showing up here, if only EA were interested. :(

Freeware is free for personal non profit use. A commercial entity, such as GOG, still has to get the approval of the rights holder as they are attempting to profit from the freeware- even if they are giving it away, the rights holder can argue that it's bringing them customers and therefore profiting them.
Publishers that are very much still in business would be unlikely to give their approval to profit from their freeware to what they see as a competitor (in that EA would prefer you use Origin for example). I've no doubt that is why we don't see Daggerfall and Arena on GOG as free titles- Bethesda won't allow it unless GOG pays for it, even though those games are free.

With some 'ifs' attached, a limited number of freeware titles might not be a bad thing.

I'd love it, just for the convenience of having most or all the games in one place where I can always download them.

I've already bought at least one game that's free elsewhere.