That really depends on implementation. I would argue that a class built around making gadgets and grenades would not be martial. Here are two possible powers for a grenadier/gadget class, the first one wouldn't be martial, while the second one is martial. (Please forgive the sloppy/incorrect formating)DonAdam said:A well-designed gadget/grenadier class would do fine as a martial controller. Think tanglefoot bags on speed.
Firebomb
You throw one of your custom-made firebombs at the enemy.
Encounter
Standard Action
Target: Ranged Burst
Attack: Dexterity vs. Reflex
Hit: Do 3d6 points of Fire Damage to all creatures in affected area.
Big Boom
You time one of your bombs to explode with maximum effect.
Encounter, Weapon
Standard Action
Ranged weapon
Requirement: You must be wielding a grenade-like weapon
Target: Ranged Burst
Attack: Dexterity vs. Reflex
Hit: Do 2[W]+Dex damage.
In the first power, the flavor is that of the user throwing a bomb they made themselves in imitation of a spell. In the second, the PC throws a bomb that anyone can use and gets more effect out of it than anyone else. I argue that the first example is not a martial power, but rather belongs to a Mad Science or Artifice power source.
Of course, for there to be a martial class built around grenades and gadgets, explosives need to be fairly commonplace in the world. While I can imagine a Martial Controller class built for a modern campaign that is built around grenades and suppressive fire with a machine gun, I am not sure that concept would work for your typical D&D setting.
I do have no doubt that someone will eventually make a really good Martial Controller though. I would like to see it happen.