I have not yet faced Ogre's at all yet alone gunline. So this is pure speculation. SO I set about planning a Gunline Ogre list for my Wood Elves/Bretonnians to fight
My first thought is, panic...after a while I calmed down a little and started to examine things.
Now Ogre's although big, scary and capable of damage at range and in CC are not without their downsides. The standard ogre bull comes in at approximately 30 points and has impressive Movement, Strength, Toughness, Wounds and Attacks.
Immediately the standout factor to me is the low Leadership (ok Average at 7) how many times in games have you rolled above a 7 on your leadership tests? I know that I have multiple times and fortunately my BSB/General was within range to allow a re roll.
The other factor is the range of Initiative at 2-4. So this is obviously great for spells that force casulties on failed initiative tests....we all know them so I wont go into them.
Finally since they are effectively an army of monsters, thankfully you are not going to experience a large amount of troops, so armies such as Skaven, Goblins and to a certain extent The Empire can attempt to swamp these units in combat and lock them in using steadfast.
Bretonnians can shatter these units on the charge (with a Lance or 2!) and due to thier special formation can expect fewer losses in return.
Wood Elves, this is what I hope to be playing a lot of again. The advantage of MSU as I see it is that you should outnumber your opponant in terms of units and that would be your strength. You force the Ogre player to either focus all his fire on a couple of units or overkill against one unit, you are taking the fire of an entire army on a 120 ish point unit (I'd gladly make that sacrifice) while this is happening, focus all of my fire on one unit at a time forcing panic tests and hopefully making the unit flee (leadership 7!) if a unit runs I WILL ensure that it leaves the board so will escourt them off the table with an Eagle, Glade Riders ect.
Just a few thoughts to start this rolling!