So, something came up recently where someone called Mekton Zeta overly complicated. The word "crunchy" was used, as well as a bunch of hyperbole about having to calculate gigawatts to drive generators and such.
It might very well be experience with the system- over twenty years worth - tinting my glasses, but I don't get it. To me, it sounds like someone flipped through Mekton Zeta Plus, saw some numbers and some systems that they didn't yet know how to use, and decided that it was GURPS Vehicles or something. Yeah, there are a reasonable number of moving parts to have to keep track of. A good spreadsheet helps; not because there's complex calculations, but just to help keep things straight. All of the math is straight arithmetic, and most of it is tallying values. But it took me about an hour to create a cybertank over the weekend, and that was without touching the build system in a few years. Sure, there are some things that I do that aren't standard procedure. For example, I don't try to reduce individual systems to fit within the space available. I tally up the total available spaces in the design, subtract the amount of space that's being used by the systems, and then just buy space efficiency if needed because it's so damn cheap.
I have the same reaction when someone talks about the Silhouette construction system - specifically, the one in Jovian Chronicles or Silhouette Core - being complicated or requiring a lot of math. While it's true that there are some exponents and cube roots and formulas in the construction system - it's also entirely optional. You only do it if you want to generate Threat Values (for balancing, although they're kind of useless for that) or some other fluff values like price. Other than that, the build system is less complicated than MZ by an order of magnitude - you pick the size rating, choose the armor rating, give it some propulsion, stat out a few weapons, add some perks and flaws and you're done.
In systems like Mekton Zeta or Silhouette there's going to be some domain knowledge or system mastery involved in making the right decisions - how much armor to put on, how much damage a weapon should do, what's a good range or movement speed, etc. That's a given - a potential GM or player just needs to design a few mecha and face them off against each other to get a feel for it. But the construction systems themselves? They're really not that complex. GURPS Vehicles? That's complex. MegaTraveller? That was complex. Mekton Zeta has more in common with Car Wars than the former two.