I've played on many builds, you always have to sacrifice something when you go for one build. What works against 1 build may be completely useless against another. And coming out of cover against a bot that can kill you in few shots, if aimed straight at the body is in no way a smart decision if you don't have a similar build and trust your aim, which you can't really trust due to the difference in ping, which makes it a pain.
For example, using mines for defence can be compromised if your opponent shoots them off, which would leave you disadvantaged, with less HP or weaker weapon build, this would require you to use a build without devices at all, or maybe turrets or shield could work, shield is too bugged though, it doesn't always open, people can drive through it, my brother told me that 1 player drove through his shield twice in a row once, one time could be explainable, since on his screen he might have passed the point of where the shield was planted, but going through it again is just unexplainable...might be it didn't open on the other players screen.
What I'm saying, there is no perfect build, if you want speed, you go for weaker parts, which can be destroyed by both, high damage weapons, as lasers on triceratops, or even the mines, if a fast bot drives on mines he can instantly lose his chassi and become immobile. The gameplay b4 the devices were introduced was very different and sometimes even games 5 v 5 lasted not much more than a minute, since everyone would just go to the center of the arena and shoot at everything that moves, very fast games, but with introduction of devices the old builds that were aimed at high speed and decent damage turned out to be not so great if you decide to drive through whole arena, since there might be a trap waiting for you around the corner, which you now may not be able to run from, I could go on and on with the examples, but I think I've already made my point.
Everyone chooses what's best for him, can always change the build during the day, if your opponents use something your build is not suited for...
IMO warhawk is not suited for a low rank like 4 or 5, it would be better for rank 7.
P.S. can't always fight against the bots and feel like a boss, sometimes you run into real players, ya know xD
On this note I'd like to suggest either removing bots, either making them stronger and appear on higher ranks, also using the devices.