TL
R
Burnas can mishap in the movement phase on the roll of a 1 and blow up (if they roll badly on the mishap table)
Burnas provide 4+ cover for all units within 2" ( potentially could pump it up to a 3+ for the burnas themselves or give the unit shrouded)
Meks are partially there to watch over the Burnas so they add rerolls on the mishap table 1 per Mekboy (Including big meks)
Burnas are now bulky, If a mek is in the unit and the unit mishaps inside a vehicle it always count as rolling a 1 (Mekboys care about their toys)
I guess a speed of play change could be to just have set averages for the wounds a loted for the blasts
Ok, so basically the idea is to increase the utility of burna boys by themselves, Kommandos and Lootas are pretty efficient on their own as units, but burna boys aren't.
You have to give them additional assets like transportation, or somehow walk them behind a wall.
So, my idea is to give them a buff, and a nerf...which (hopefully) in total increases their utility on their own, while not breaking them, and giving them a bit more fluffy characteristics.
So the idea is to do something similar to Stormboyz, on the role of a 1 in the movement phase, they get bored and light someones pants on fire. They're pretty keen on fire as a group, and so they've gained a bit of a resistance to it. A roll of a 5+ and the Burna notices his pants on fire puts it out, and then randomly krumps a nearby ork whom he thinks lit him on fire. (fluff a random burna suffers a wound)
on a 3 the ork gets the fire under control and wounds a random nearby burna/ 2 and the unit suffers a small blast template no cover save/ 3 and the unit suffers a large blast template no cover save (dunno what the strengths aught to be)
Adding a Mekboy lets you re-roll the mishap table for however many Meks you have in the unit (including big meks)
The upside to giving Burnas this sort of mishap table is that now, they become mobile cover, like the Bikes, everyone in 2" around them gets a 4+ cover save
To further differentiate different uses of Burnas we could also consider making Burnas bulky, and add modifiers based on being in vehicles, something along the lines of "Meks pay more attention when their toys are at risk."
Thematically orks and smoke/clouds make sense so potentially I could see this unit giving everyone in 2" shrouded. That would potentially open them up in stealthier lists using kommandos. I don't honestly know...I'm just trying to think of interesting ways to pump Burnas so they can stand on their own without the support of walls or transports.