If the special grenades became an addition to your frag grenade, using one would absolutely be worth it. But the situations they are just so rare (even though they shine in those specific situations) that it's not worth the investment. And the situations can't really be manipulated to happen like some other situational options in weaponry across the classes. My personal experience on the last medical applicator upgrade was (and is) really great. The extended range and time saved reviving means you can do run-by revives, and the 100% health the friendlies pop up with means they die much less even when you're doing the reviving under enemy fire (so long as the enemies aren't in close quarters of course). That last upgrade feels better than going from unupgraded tool to lvl 5 tool.
I'm sure you have had awesome kills with revive grenades. I argued earlier that the fully certed med tool should be his first priority, but he didn't want to max it. I was letting him know what I thought useful upgrades were that he could pick up, depending on his playstyle. If you want to turn this into a hurrdurr pissing contest, I can oblige. You have 107 hours of medic. Trust me, I have 211 hours as medic.
i didn't want to start a "hurrdurr"contest, but i don't like to say: "hey, i'm good. i have played XXX hours" that just looks a bit like a bighead. but let's stop here. and lvl6 medgun is really worth it.^^
