Fear the Reaper?

REAPER
- New versatile infantry unit, touted as a raider.
- Excel in mobility thanks to having the ability to 'cliff jump.'
- Hit and run tactics are important, given that they can't take much damage.
- D-8 demolition packs that do terrible, terrible damage.
- Often accidentally called the "Raider" by senile coots like Toastmold.

Toastmold
The Reaper seems like it is an amazing unit. Could it even be too amazing? It looks like this fellow is made early in the game, can cliff jump into your base, throw down a bunch of time bombs while mowing down your workers, then giggle and zoom away before your defenders arrive on the scene. Who knows maybe it could even easily dispatch them too if the user was skilled enough with D-8 explosives. And when you throw in stimpacks and flying fridge-medics I'm a little worried that this unit will turn out to be tricky to balance.

Lucidorf
Good riddance to the Vulture. I applaud Blizzard for introducing a brand new unit that takes up the old role of the Vulture as harassment unit. At the same time I'm concerned with the Hellion, which looks to have a relatively overlapping role. Now, when it comes to balance, then I wager there will be a lot of outcry over this unit. Good players should be able to use it to its full effect, while novice players will have large problems to defend against it. However, as long as the bombs are researched higher up in the tech-tree, then I think it should be pretty balanced unit.

zkss5
I'm very concerned about this unit. Its speed seems awfully low for a unit that ought to do a fair amount of scouting and flanking. Its range is so short that its ability to cliff-jump seems a lot less useful than it ought to be - in the second battle report, the pack of Reapers couldn't attack the Zerglings trying to break through the rocks from the cliff; they had to jump down to their level. Putting D-8 mines aside for the moment, this unit seems like it's only useful in fighting things that can't fight back. Woo. Every unit is good at fighting stuff that can't fight back. These guys just aren't feeling nearly as versatile as they ought to to me.
And as for D-8 mines, I hate how they're shaping up. Fighting Stasis Trap wards in War3 was friggin' obnoxious, and these things are using the same mechanic. I think crap like this and the Nighthawk's Hunter Seeker Missiles (which are using the same design mechanic) need to be removed.
Overall, a unit whose sole use is to jump into a mineral patch, mow down some workers, then jump out is too narrow and uninteresting as far as I'm concerned.