Beriothien wrote:two walkers operating together with shuriken cannon and star cannon
While it isn't your question, do yourself a favor and don't ever give war walkers shuriken cannons. The walkers are frail and their best defence is range. By giving them a weapon that forces them into the range of bolters and most other basic weaponery, you are just asking to get your walkers killed. Spend the couple of extra ponits and get them scatter lasers instead of shuriken cannons. Not only does it increase their fire power, it also increase their life span.
Now to the question at hand. I find that upgrading your scouts to pathfinders is generaly worth it. The fact that you double the number of
ap 1 "super shots" that the squd puts out is quite valuable. In addition the unit goes from getting 3+ cover saves in most terrain to getting 2+ cover saves. That is worth it's weight in gold. 2+ saves are very very difficult to get though and it makes the unit not worth shooting at. As far as pinning goes, while it's powerful when it goes off, the fact that it relies on your opponent failing a leadership test makes it very unreliable. Leadership 8 units have a 72% chance of passing the test. It goes up to 83% for leadership 9 units. So while something will fail eventualy, the odds are 1 out of 4 or worse.
A word of warning. One big mistake I see all the time with these units is using the infiltration ability incorrectly. The advantage of infiltrate for these units is that it lets you set up last and see what the best spot for you will be. The ability to deploy outside of your deployment zone should almost never be used. These units are long ranged killers. They are no good in hand to hand and are vulnerable to short range fire (they die in droves to flamers). The last thing you want to do is be closer to the enemy than you need to be. So do yourself a favor and make sure that you don't start closer than about 30" or so from the enemy. Anything less than that is just asking to get yourself killed.