@sundancer
With the average GW kit you can only ever build 1 heavy weapon dude, because there’s only ever one in a squad. The assembly instructions are also very clear in what type of squad you’re building (follow 1-10 for variant A and 11-20 for variant B).

As such it is next to ‘impossible’ for someone to make something that wouldn’t work with the average GW kit even if it does have ‘options’ (unless you deviate from the instructions and forgot what type of squad you were building … and even then you can’t build two leader characters by accident).

I’ve noticed that the Deadzone starter set would allow me to build several and that may or may not be ‘legal’ depending on how many ‘normal’ troopers you’ve got.

Bolt-Action is a bit of both. You need to decide who is going to be the officer before building the squad, because it is possible to build multiple figures that could count as an officer within a squad. Heavy weapons tend to be limited to whatever is on the sprue, but regular trooper options can vary. Some armies have more squad variants where things that are ‘illegal’ for one are ‘legal’ options for the other, which means you need to know what you want to build before assembly starts.

Less thinking makes it easier for players to create the ‘correct’ squad without having to worry about doing anything ‘wrong’, which can be a good thing for starter sets.

// — edit —

Until @torros mentioned it on discord server I kind of had forgotten about the one game that had peaked my interest recently :
‘Divisions of Steel’
Created by the same author as MeG this could be a nice alternative to both Flames of War & Battlegroup.
It’s digital only at the moment, but the rules and army lists are for sale already