This looks like Horde mode to me and not campaign, but yea I would agree that Gears to its advantage has more enemy variety and perhaps larger arenas, and that certainly mixes things up a bit. The Order isn't exactly always constricting of mobility and cover options though (as the bridge level shows), and does also offer other things in it's combat that also offer strategic diversity, like secondary fire options on certain weapons, as well as bullet time for example, which can be used to shoot grenades mid-air and things like that.
I think with games that feature majority human enemies, like COD, Battlefield, Killzone, The Order etc, and lack the enemy variety of games like Gears or Halo, variety is less in enemy aesthetic and characteristics, more in the different weapons they use (Eg sniper, rocket launcher, shotgun, Thermite rifle etc), which can require slightly different tactical consideration, though maybe not to the same degree as games that completely switch up enemy types (which The Order does with the Lycans).
A lot of us discussing it now haven't played it yet. There are a tonne of impressions linked in the OP, and the vast majority are positive. So that's not necessarily the case.
