ELEX is not quite as good as Gothic 1/2 as an overall package, especially in the context of their respective release eras. But these are 2 of the greatest RPGs ever made, so just because a game isn't quite as good as them, doesn't mean it's not good in general.
Moreover, ELEX is actually better than G1/2 in some ways. I will go over the comparison below in detail:
Exploration: Both G1/2 and ELEX are great at this but in different ways. All 3 games have a lot of hand-placed unique content, but G1/2 are smaller and tighter, with less space but more content per cubic foot. ELEX is huge but pays for it with less denseness. Also, G1/G2 handle vertical exploration with climbing of walls and surfaces, whereas this is still available in ELEX, but mostly the player utilizes the jet-pack to get around in the third dimension.
Writing: This is one area where ELEX is actually better. The main story, twists, and the general background lore are more exotic and interesting than Gothic's generic fantasy. In both cases though, the writing is very functional and down to earth, no modern emo-loredumps.
Quests: Again, ELEX has more quests than G1/2 (around 500 total), and the quests have more C&C on average. Many of them can be done in different ways, have more consequences, and present more choices.
Combat: The combat in G1/2 was better, especially for the times, but at least ELEX's is not as bad as Skyrim's. It suffers from small budget and lack of time, but overall, has enough depth and challenge to be mildly entertaining.
Graphics: At the time they came out, G1/2 were better looking, but in absolute terms, ELEX of course looks better now.