Quick note on the Crab 45 --- it fills a role that some of the IS units do not have. It's an "encirclement" machine .... remember, where other forces work from single mech, to lance.... the WOB works from single mech to Level II, which is 6 mechs .... and so while the bulk of the unit is engaging directly, there is a role for a design that can encircle the enemy, using the C3i to cover for the fact that it is racing around at medium, or even long range... to keep itself from presenting an easy target, while going for back shots ...
If done right, it forces your opponent to choose to continue facing the bigger units, in it's face, or turn away from them to go crab chasing ..... and being a medium, as opposed to a light, you can handle a bit of knock, if the opponent has anything back there.
Some other units in the IS can use the same tactics, notably Liao and Marik, with their vehicle reinforced lances ......
Nahuris