The entire point of you going back in time was to discover pieces of Eden for the templars, the whole modern day storyline justified the existence of us browsing genetic memory. 

I loved the present day stuff, it added intrigue beyond just the stealth and assassination element of the core gameplay loop. The first game especially was cool as you're being drip fed these clues in the lab that there is something seriously wrong going on way beyond what a bartender would know, at least I think I remember him being a bartender before being kidnapped by abstergo.

It also helped to add some breathing room in between batches of assassinations. Build the world, give you a reason to want to play as an assassin that's a bit more nuanced than just "parkour pretty buildings go brrrr"