Well, this certainly looks like good news. For a start, the snipers sound good, that is if snipers are tweaked in 5th ed to not be totally useless, as I hope they will be. The "Chain of Command" thing sounds both useful and fluffy. No more abuse of Doctrines will be quite nice too, although I imagine that there will certainly be some scope for powergaming with all these fancy new things. The new Russ sprue sounds great, especially as it will mean no more £30 Demolishers, and could even mean that Exterminators or something like them will be in the codex. Plus there's bound to be a way to be able to swap turrets, allowing for much more flexibity. Although in a way I'd almost be disappointed if they made a plastic Exterminator turret - I was quite looking forward to converting my own out of heavy weapons bitz. Ah well...
One thing I always wanted for IG is a squadron of "spotter Sentinels" that can make artillery more accurate - give them little or no weaponry, and a big fancy range-finding thing with lots of vox-caster ariels and other such gubbins. Cool and fluffy, and very handy for Basilisk fielders...

We won't see any official models for such a thing in all likelihood, but it'd be nice.