I've always had a soft spot for the Battle Hawk, probably because I like slow lights in general (even while acknowledging their limited utility). The original strikes me as best when you keep it away from the front lines. With an energy-heavy armament and streaks it can function as a raider, especially if the enemy is using low-quality assets to protect outposts while the good gear is sent to the line. It's also a good trainer, with the TRO entry rightly noting that pulse lasers are very forgiving for newer warriors. I could see these filling out Training Battalions and lighter academy Training Cadres. The garrison forces a lot of them were shipped to is, luckily enough, another good place for them. If the combat you're most likely to see is scumbag pirates in old mechs, the Battle Hawk is quite functional. It's a particularly adept bug hunter, being scarcely slower and able to rapidly punch through their weak armor, with the pulse bonus negating any TMM advantage they might have hope to gain via jumping. It's good against light vehicles as well. Because of it's bad reputation, particularly with the LCAF, you might be able to pick some up relatively cheap too. I like the -K306 even better, with its far greater range on the MLs, more durable engine, and overall (slightly) greater firepower, though I probably would've gone for a TC in lieu of extra missile tubes, because the pulse bonus is the one thing I really miss from the -K305. I'd be interested to see one that replaces the AMS with an electronics package of some sort, either BAP to increase its utility as a scout or GECM to help it survive and befuddle enemy scouts it's hunting.
All in all, it's a great little mech if the only opposition you're worried about is fairly light and/or outmoded, though it does lack AI capability, now that streak-2s can't fire infernos anymore. It would be a very good mech for low-end mercenary units that specialize in low-danger garrison and/or cadre contracts, or as the "heavy support" for a mercenary group that's dominated by infantry or light armor (think of the utility a group like Stalwart Support would get out of a company of Battle Hawks!). just don't take it up against modern heavy or assault mechs unless you've got plenty of buddies.