I wanted to play the current beta for a while before posting about this; basically, as it stands right now, there really feels like a sort of "dead zone" of missing mech niches in the game. I'm trying to avoid this thread from turning into a "post your favorite mech chassis" and even about chassis in general as a rule, with one exception (as I'll say before) but more for a hope that in the next beta, some variants might be added or moved.
Really, I got talking about this while looking at the next planned mech additions; some just seem to be redundant such as the Commando (as much as I like Commandos, the Owens can fill every single role the Commando could in terms of performance and loadout), while others feel like a really missing section - such as LRM-heavy mediums (Hellspawn, Trebuchet, Apollo, etc) or Medium-Heavy laser heavy designs for the IS (Black Knight, Crab, Lancelot). As far as faction-specific tech I do have to admit, at the moment only the Bushwhacker feels like a "proper medium" for the IS, with the Uziel's light armor making it a hit & run mech and the Hollander being far too gimmicky in origin, with it's easily blown off gun to make me drive it and I'm a bit concerned that once the new Clan mediums are added the gap is going to get even worse.
Please keep in mind before you reply this isn't a thread to suggest those chassis are added to the game (I realize that is a huge undertaking!) but rather as justification to consider adding variants to make up for the missing areas. As it stands, you're not likely to find more than one Large Pulse Laser before you hit assaults, or a mech with nearly as many LRMs as an early-game tank in the mid-game and it tends to cripple your choices, in particular if you look at it on a per-faction basis. I would very much be satisfied with, while outside of perhaps the original spirit of the designs, a arm-laser heavy Hollander or a missile loaded Uziel!
The main reason I'm posting this is, in the mid-game when graduating from Lights to Heavies, I really hit a "dead zone." During this time I either end up staying in a light, or purchasing a specialized tank, with no real front-line mech options available to my play style and that really hurts that part of the game for me - and I'm sure I'm not entirely alone on this. Again, I'd be entirely happy to see variants to fill in these gaps since it'll be a while before even the planned chassis are added. In particular, any variant with weapon groups scattered over different ranges and travel times could definitely stand to be replaced as I cannot imagine they get taken very much, and are simply not as effective as other available options in the environment of LL where simplicity in weapon group firing is a huge advantage.