You don't really need any mods to ANNO2070, it's complex enough as it is. Although there is a big mod that improves mainly the science possibilities (forgot the name) that seems quite nice. Most other mods that I heard of are cheats and if you use them at multiplay or conquest, you might be excluded from the game.@Nilla
2070 is the fifth game of ANNO. As i said I've played them all. The first one 1602 came in the late 1990ies and to me it was something completely new and different.
probably you speak of "Year 2170: ARRC - Advanced Research - Reformed Content" that adds new buildings and production chains.
but perhaps, as you say, it is better to play the first vanilla that really has a lot of content!
I decided to play five years of alternating Banished to 5 years Anno 2070 (if the time is comparable)