I can only add to what everybody says - the PTS Mech Select screen feels like an attempt to make mech selection as cumbersome as possible...
It could be so easy - just have a list of all mechs with column heads that allow sorting and filtering (like e.g. the column heads in an Excel table). Columns could be:
Faction, Tons, Chassis, Variant, Custom Name, XP, Firepower, Heat Efficiency, etc. Actually, if the players were able to choose which columns to display in such a list, the mech selection screen would be perfect.
Alternatively: Just have tiles like in the current live mechlab - ideally with the models displaying the correct camo and colors. Or even better: Let each player choose (via game settings) which of these mech selection methods (list or tiles) s/he wants to use.
Finally, it should not take a player more than a single click on a tile (in tile view) or a line (in list view) to select a mech for the next match. Likewise, double-clicking a tile or line should take the player to configuring that mech in the mechlab.