One of the problems I see is a lack of ability to deal with hardened targets from long range (no Lascannons, Missile Launchers). Because it's pretty much geared for Footslogging or Stand-and-shoot, the big problem I see is that a turtly army is going to be lots of trouble for you. If I were to run this...
2x Tactical Squad - 6x Marines, Lascannon, Plasmagun
2x Devastator Squad - 8x Marines, 4x Missile Launchers
Dreadnought - Lascannon, Extra Armor
Whirlwind
This would give you a lot of trouble by itself, and that's only 840 points of my build. If I build the rest of my army with counter charge (Bolter Screens with PF Sergeant and True Grit/CA, Assault Squads w/ PF Sergeant and Plasma Pistols), I wouldn't be too worried. It's going to take you about 4 turns to get across the board and each turn, you'll be taking 3 Lascannon, 8 Missile Launcher Shots, and the Ordinance fire from the Whirlwind. Without taking into account deaths from the Whirlwind, this will (on average) kill 6 marines a turn or 24 marines before the Assault charge. This means that half your army is dead before you get to touch me from Lascannon/Missile Launcher fire alone. With Bolter Fire, you're looking at 3 turns of 3 deaths (plus the rapid fire turn adding another 3) and the Plasma Guns will add another death per turn for 3 turns (with rapid fire on the last turn for another death marine). This will make it 40 dead before the assault, leaving you with 15 guys to have to deal with my 2 Counter Attacking Tactical Squads w/ PF Sergeants, 2 Assault Squads w/ PF Sergeants and Plasma Pistols, and whatever is leading them (in my case a Codicier attached to one of my Tactical Squads).
Because the list lacks the ability to close quickly and it does not force the enemy to want to close, on a tactical level, this would be pretty tough. With True Grit/Counter Attack, I've determined that the only way to make it really successful is to give the enemy a reason to come and assault me while I shoot at them. When I do receive the charge, they eat it as hard as I do but they will have to endure all that shooting first, making it easier for me to survive the assault. This list lacks that aspect as all weaponry is pretty much geared towards close combat or close quarters shooting, thus giving me no reason to come after you.
If I were to pick a trait for a footslogging list I don't think I'd go with Trust You Battle Brothers, but would instead go with Infiltrate, making the footslogging phase less scary and shorter. In this case, you'd only be looking at 2 rounds of shooting (resulting on average in 21 deaths instead of 4

.
I know that terrain will make footslogging easier for casualties, but it will also take you longer to get into combat because you'll to navigate through/around it, leaving your guys walking instead of killing for an extra turn.
Just my opinion.