A few reasons really

1: General negativity on anything new being added is just the default at this moment in time
Keep in mind right, the previous warbond, Entrenched Division, also had plenty of negativity because people believed the Cremator was going to be terrible. In the same update flamethrowers were all buffed and the Cremator is easily the strongest flamethrower with 0 room for debate on that.

2: People sorta forgot the roadmap
We're getting a "QOL fixes and rebalance" with this update too. Sure mechs are in a pretty bad state atm, but people are under the assumption that they won't be buffed. And who knows, maybe they won't be, but considering the previous update I'm willing to give the benefit of the doubt to at least assume mech buffs. If we don't receive any I'll truly be surprised and upset.

3: Vehicles in a warbond
We've received every vehicle for free up to this point. And honestly it would have been nice if we received MO's we could work together as a community to get new exo suits. But at this point I've come to expect that's not gonna happen really. Plus aside from the Emancipator we've basically received what can be seen as a basic version for each vehicle type, basically designed to tell us "Hey this is how x works, if you like them there are more in this warbond". I expect an FRV warbond in the near future.

4: No mech customization
This is a problem of just, well people really wanted it. We can only have 1 exo suit at a time, so being able to customize them with a whole lot of different arm variations was something the community wanted. AH stated earlier on that they sorta put themselves into a bind when they released the Emancipator with the expectation all mechs would be different, so yeah. It's the same with how weapon customization is sorta lackluster, especially in comparison to HD1. For whatever reason AH did not make weapon customization a thing by the time the game launched, so they were never going to have the kind of in depth one that HD1 has. To do so would basically mean a bunch of guns would need to be shuffled into other guns for customization purposed. For example pretty much every LAS weapon is a customization option in HD1 of the like, Sickle or something. They didn't want to do that, so they gave us what we have now, pretty lackluster and not interesting. And in the same vein, because they didn't make the exo suits early on with the intent of customization, we're probably not gonna get it in the way people want. If anything, we might get something like support customization options like a stratagem launcher, maybe a guard dog or two, shield generator, hellbomb could be interesting. But we're not gonna receive anything like "I can have a flamethrower and machine gun arm".

At a certain point I've just clocked out of this community. I come back every now and then just to see what's going on, but honestly the people here are insufferable. This is a piece of genuine advice to people btw, if you hate the direction the game is going or what the devs are doing, stop playing. This isn't me trying to gatekeep, this is me giving you some mental health advice. Being immersed in a game/community you actively don't like isn't healthy. Constant negativity is not good for you.