You're right, however, that was one of the reasons I upgraded too. This one can handle the full 2.5 gigs even with IDS on.
What hardware are you using? I'm not seeing near my advertised (and previously achieved, via Acer 'Gamer Router') with IDS on.
IDS is probably overkill for a home network anyway.
I recently replaced said router with a Dream Router 7.
Ah haven't looked at their current offerings in a while, I am still on the first gen USG 1000fdx but hand-rolling a 2.5 router (Radxa E52C, it's nifty) to replace it when I stop being lazy.
You are right about Unifi's software being pain and I love that they keep changing the UI, the controller on the server side is dependency hell, and mongodb to boot just in case you need to manage n^webscale deployments.