See, this is where you and I part company
You're saying that your weapon has a weakness (slow RoF), and that it makes you vulnerable when attacking similar units - APCs etc.
Now, here's what I do on maps like Fool's Road, where there are several friendly units with the Rarden: Buddy up.
If you've got a Scimater and a Warrior together, you can combine the benefits of having a mobile platform for an infantry squad and effectively, an increased RoF from the gun. You also get the advantage of being able to have one gun loaded with HEAT and another with Sabot rounds, so you can instantly engage any units you come across, regardless of their type.
If you combine three or even four of the 30mm-cannon equipped vehicles (two Scimaters and two Warriors on 64p Fool's Road), you have four times the RoF. If all four units get their eyes on the T-62 and fire their first shot before the T-62 sees them, the tank will go down and will take maybe two of them out at most.
Alternatively, use hit-and-fade tactics to hit the enemy APCs if you're alone. Smack them, then run for cover. Wait for them to look for you, then hit them again and fade out. Relocate behind them, and then get some more quick shots onto them. Crewmen no longer have a wrench, unless they've got an engineer with them you'll be able to take them down that way.
Finally, use the terrain. If you get into a good hull-down spot (and Fool's Road has some positions that are brilliant - there's one in the NE area of the map where you can get so hull-down that only your gun and aerials are visible) - then you're far less likely to get taken down. My gunner in the Warrior was disconnected a few weeks ago, and no-one else in my squad was available to gun for me at that moment in time. The rest of the squad were on foot and getting hammered by a T-62 at the Airbase. I got nicely hull-down and waited for him to leave the helipad. He blitzed straight past me, and when I opened fire at about 300m he was unable to score a direct hit on me. I got enough Sabot rounds into him that he caught fire and bugged out; I followed and finished him off before he'd made it around the corner. I hate to say it but a solo'd IFV managed to kill a two-up tank
