Guitarpima
You can do swells in BFD Eco. The latest one anyway. Only the interface is less than awful so I only use it when I need swells.
I'm not sure how you do cymbal swells in Eco and the manual says nothing about them but trust me, the cymbal swells in BFD3 are superb and nothing like BFD Eco. It's a completely different process and I don't know of any other product that can offer the same right now.
As for the upgrade price, bearing in mind the upgrade from BFD1 to BFD2 was $125 6 or 7 years ago to have only risen by $24 is pretty good value for money.
I'm not allowed to give any product details but as for the UI some will love it, some wont but if you've seen their other more recent products such as Tremor and Geist then I'd say it's more a move in that direction and is almost as big a change as was from BFD1 to BFD2.
Personally I loved the look of BFD2, the mixer was bigger and clearer than any I had seen at that time and it was just, sexier IMHO
Hopefully I haven't overstretched the terms of my NDA
Steve