I'm currently learning about various 'Mech variants and reviewing official source materials (TROs and RSs) for a mini-mod of Battletech Revised. In HBS' Battletech, armor values are linked to structure values and BTR imported this without changing it, but I aim to create new armor and structure values for every 'Mech implemented in BTR. This would mean, for example, that the Awesome really does have incredibly thick rear armor, rather than sharing values with other 100 ton assault 'Mechs.
I'm striving to keep the 'Mechs as accurate to the record sheets as possible but where necessary changes are made, like when there's excess tonnage, I usually add another heat sink or more ammo. I also hate obvious cases where the designers ran out of room to place things and just put them wherever, or even left them out (e.g. the Endo-Steel chassis of the HTM-28T), so I try to fix them up. This does not happen often, however, and the things that make a variant recognizable and distinct will never be touched; in particular, weapon systems are sacrosanct. This also goes for whatever new -RV variants the BTR crew have introduced. I also aim to correct any errors on the part of the BTR crew, intended or otherwise, and introduce 'Mechs they might have passed over or missed and I believe should be included. I have already modded in a multitude of other changes, and adjusted the weapons to be truer to CBT values, though with my own twist. I hope to make a contribution to the popularity of BTR, which I believe is the best non-Clan mod for HBS' Battletech.
On that note, I despise the Clans. Imagine following a highly respected war hero into the unknown, only to be rewarded with ejection from the military into a labor caste. The obvious choice was to create a Universal Army (see Fredric Jameson: Universal Conscription and the Citizens' Army), which would make any attempt to establish a caste system appear as ridiculous and socially regressive as it is. Imagine believing that war is a part of human nature and then ensuring that war remains part of human nature and considering this a solution. Nicholas got what he deserved in the end. Anyway, as an antagonist they serve their purpose. It's just obnoxious how literally everything has to be orders of magnitude better than Inner Sphere tech (examples of which would fill several ranting pages).
Aside from that, I have recently released my first mod over on Nexus called "True Argo Upgrades", which implements the actual costs of running the Star League-era ship in the early 31st century. Over on the official Battletech forums head to the "MechWarrior and BattleTech Computer | Console Games" section and see the "Argo running costs" thread for a full breakdown. Eventually, I plan to implement post-3040 costs so it can be integrated into the many mods that start at the Clan invasion or later.
In general, I much prefer Battletech's space opera style than the childish stuff you find in the likes of Warhammer 40k, despite its many flaws.