Anyone claiming the Orion as the main Marik trooper for the purposes of this thread needs to go read the OP again. We're specifically looking for medium-weight 'Mechs, and the Orion as much as I adore it certainly does not meet that requirement.
I suppose one of the issues we're all running into here is we need a definition of a "trooper 'Mech." Are there speed limits? Weaponry requirements?
I hear ya, the discussion just shifted in the direction of "signature 'mechs" for a while there. Some in the discussion had shifted the conversation toward signature 'mechs of each House as at least one way to identify or classify what "trooper 'mech means. So that's where that came from. But yes otherwise heard and agreed, the OP is looking for a specific weight class and that got lost (even by me) a little there.
We seem to be all over the map in terms of a definition of trooper 'mech. I've heard a lot of people say 4/6 medium. But I have to agree with the point that 4/6s mediums aren't that common among all factions and that in some factions a 5/6 medium is perfectly viable as a trooper 'mech. I do think there are some perfectly good 5/6 mediums that can hold their own. They just may be a little more dependent on making the most out of mobility and/or teamwork to overcome any shortcomings in firepower or armor that they may have.
I do think, weapons wise, they need to have some semi-decent capability to hit at range, especially if they are a 4/6 machine. Which is why I think a lot of us are reluctant to classify the classic Hunchback as a trooper 'mech. That seems to be one point of consensus that I'm seeing.
I find myself increasingly thinking there isn't one good definition of a trooper 'mech, but a few perfectly different perfectly viable concepts, and as long as you play to the strengths of that particular design, and make good decisions on the battlefield, it can probably work.
This isn't a problem unique to this. Over the years I've seen many discussions along the lines of "what's the best qualities in a fire support 'mech?" or "What's the best qualities in an assault 'mech?", or "what are the best qualities of a scout 'mech?" and found a lot less consensus than you'd think. Lot of opinions out there, and they don't all align.
Which is fine, if we agreed on everything, then certain designs would always get used, while others would never get used. That would be an indicator that the game is unbalanced in some ways.