I'm afraid this is not a very strong list. 40 infantry troops is rather low for a Mordor army of 700 points. I like the warg contingent, true trackers are better, but not necessary. Remember in addition to shooting your warg riders can jump lone stragglers in hand to hand combat. Threats like this can help keep your opponent in check. The troll I'm afraid will most likely meet an untimely death. You have too few Mordor orcs. The lowly orc is the most important factor in any Mordor army. The orc is the shield against enemy archery, the bulwark that holds off the enemies heroes, and the helping hand that insures your heroes win their fights. Without enough orcs a Mordor army can't succeed. (I know I've posted this in another thread, but all Mordor generals need know this.
) You don't have a banner or shaman. Either one of these will really improve the performance of your orcs. A drummer would do the same.
I suggest getting ride of the Mordor Troll and the Morannon orcs in favor of more orcs, Mordor Uruk-hai and a banner. For the same amount of points you can get get 7 Moror Uruk-hai and 7 with 2-handed weapon for a total of 14 Mordor Uruk-hai at 119pts. And you can get 16 Mordor orcs with shield or spear and 1 with a banner for 126 points. This gives you a model count of 50 plus banner. Now you have 15pts left to upgrade the orc captain to Shagrat (55pts) and this leaves you 5pts for Gothmog's shield. In this list Gothmog represents your allies.
Rob