The big problem with this expansion for me is that in more than one place, there are severe flaws in the way the objectives are set up. Essentially it means that in some cases, it's actually a BAD idea to achieve some of the objectives too early, because it then sets in motion another sequence of events which you may not be fully prepared for. Here's a couple of examples:
1) On the level where you first face the MARV, there's some place you are supposed to capture. However, as soon as you capture it, a new objective starts where you have to defend it. This coincides with huge waves of enemies spawning out of nowhere (including air units). The first time I was playing this mission, I'd wiped out their whole base but didn't have many units left before sending in the saboteur. This meant that I didn't have enough units in the vicinity to properly defend the structure. So next time around, I surrounded it with dozens of units before capturing it. Basically slowing the game down, I had my engineer stood outside it for a minutes for chrissakes!
2) On the final level, once you bring down the shield a 'DOOMSDAY TIMER' is triggered - meaning that if you fail to capture the tacitus before it runs out, you automatically lose the game. This is incredibly lame, because it actually PENALISES you for being too quick in bringing down the shield, before you've built up a proper attack force. So in the end I actually ended up reloading an older save, letting the timer tick down to 0:02 and then SELLING the structure to freeze the timer. Having built up a massive army and destroyed their bases, I then just captured one of the other structures to polish off the final 2 seconds.
Basically they didn't put enough thought into how they chained objectives together - they created a situation whereby the most effective/safest style of play is a very slow, laborious build up, not completing most objectives until the last moment etc, rather than promoting an aggressive, expansive style of play.