That gear inch range is pretty typical of folders, and the high is adequate, but I agree a lower low would be better for most; they may be assuming athletic standing climbs all the time, I can only wish.

A rear suspension that bobs while pedaling will definitely suck power. I don't think that applies to their front suspension. But a suspension that can suck up small bumps (like in my city, tree root bulges on cycle paths) would mean faster travel, just like cushier tires, although suspension is notably heavier. Then it become intermeshed with tire choices; cushy + rigid, skinny + suspension, cushy + suspension... I think bump size and surface come into play. But Birdy's brand identity is built on front and rear suspension, so I don't fault them with staying with that, and otherwise trying to make it as racy as possible.

Chainstays don't look particularly long, but I'm just rough eyeballing.

Reach looks generous. Handlebar height looks too low and sporty for me, but clearly that is aimed at the sporty rider.

Required replacement of structural parts every couple of years... yeah that is a valid criticism IMO if they are still doing that. Just no reason for that, especially with a new design introduction that could correct that. Ultra-lightweight race bikes don't have that requirement.