Ruckdog, thanks for bringing up this topic. Far too often I find myself in a gaming "rut", so to speak, of always using the same models and the same basic tactics. I completely forgot some of the flexibility that 2.0 affords a player that takes the time to read the book!
I've only used flanking forces once or twice, and it was so long ago that I can't remember the outcome. But here are a couple thoughts on the topic:
1. I think in the 1.1 rules, you couldn't use robots in any of your Strategic Forces. I don't see that restriction in the 2.0 rules; all I see is that there can be no massive- or large-class ships/fliers. My John Henrys got nerfed a little bit in the 2.0 fleet manual, but they're still a force to be reckoned with. Wouldn't mind seeing them come in later on my enemy's flank.
2. With the explosion of models available for the major factions, and with the plethora of minor factions we now have to choose from, it might be fairly easy to build a special "strike package" to deal specific damage to your opponent using the flanking force--something to take advantage of a known weakness.
3. To further my thoughts above, the flanking force might be a good place to concentrate ships/fliers that are heavy rocket or torpedo platforms. From the FSA perspective, I'm thinking about my PYB-2 rocket planes. Keeping them off the board a few turns keeps them alive longer (they're a bit fragile), and it gives time for my surface ships to soften up targets--meaning degraded AA when facing an incoming rocket barrage.
Just thoughts. I might be way off base. But now that you've brought it up, I'm going to start thinking about how to employ the tactic!