Makes sense since they are using a new engine for it. They have to build from the ground up essentially.
Yeah, except that's what DAI supposedly did and it took 3 and 1/2 years in between games. They even stated in the dev diaries that DAI was the sacrificial game for this gen, since they had to code RPG features into Frostbite.
Not that I am complaining about the extra dev time at all, but the engine and tools were ready for the next Mass Effect from the get go. Even Aaryn Flynn stated that DAI passed on its core systems and framework to the next Mass Effect and future Bioware games.
Theoretically, this should have led to a decrease in dev time, but either development was slow at the beginning for a while or maybe there is just a massive amount of content in ME Next, more than DAI (fingers crossed, so long as the content is meaty and connected to the main plot as much as possible. Minimize filler. Give me an extra well developed side-story or two with multiple steps, locations, secrets and characters to explore instead of 10 MMO style "kill these creatures in this area and return to me for loot").