The new "Saw" machine gun seems comparable with what we have seen of the Covenant Storm Rifle. Quick and rapid burst that is most effective at closer range. Kind of a good surprise weapon if you are being chased down or guarding an objective.
The rail-gun seems like a great situation specific weapon, great for support, anti vehicle, etc.. It does not seem to have the punch that the laser has but if combine with team DMR and BR shots would take out a Hog.
Sniper -awesome as always. I like the new sound effects as well. If you play against me you will lean to recognize that sound as me no scoping you. :)
The sticky detonator is interesting to me. Is it a grenade launcher replacement or a more accurate weapon somewhere in between a primary and power weapon? I would like to see more game play with it.
Laser looks to still require the needed time to prime and fire but still as powerful and Reaches version -if not more. Happy to see it return as it is the best anti vehicle IMO. I wish you were able to track aircraft with it. In Reach people would get in the Banshee and flip over and over while shooting, making it very hard to target them. Now with 4 not 5 shots, maybe with extra power or damage radius instead of the extra shot?