As the topic states, there are certain concepts in Battletech that don't work in MWLL. First and foremost, Battletech has a much greater strategic element, where each side can deploy varying numbers of assets of varying qualities. MWLL, however, can only have finite number of players and those players must be split evenly between teams. All their actions are purely in the tactical sense, in that the sides are positioned before the battle starts, and they must deal with the resources at hand. So there are a few ideas we should probably toss aside.
First off, Clan tech is vastly superior to IS tech : Truthfully, higher price isn't a great deterrent when money is technically unlimited. In Solaris Arena, that is much like what we have. So an accurate representation of the price along with the power of Clan mechs isn't an exceptionally good mechanic for balancing them, especially if just getting two can smash all challengers.
Double Heat Sinks vs Single Heat Sinks : The truth is that every mech can use double heat sinks. Every mech should use double heat sinks because it is the latest and greatest, the competitive technology. To not use them is simply foolish. The only reason you should do otherwise is if you wanted to field cheap, "bigger guns," with less favorable long-term performance against mechs that are using the latest technology. That should be where the IS advantage lies, the ability to field heavier mechs at less cost, but still have a few cutting edge options available to them.
Standard Autocannons : LBX and Ultra autocannons are simply superior in every respect. Standard autocannons should, again, only be deployed as cheap alternatives when big guns are needed in a pinch. Their performance should be lower than that of LBX and Ultra autocannons, as those fit the new standard of technology.
Anyone have other concepts they'd like to talk about? Anyone wish to dispute what I've said here?