How aren't our options really limited? Look at the defence.... in a 3 CB formation we only have 2 as backup who are Blackett and Keane. The main 3 Evans, Jones and Smalling (the latter 2 are susceptible to injuries), so how is this not a paper thin defence? Especially with this system. It's hardly ideal to know 2 of your 4 wing-back options are Valencia and Young either.
If we revert to a 4 back system, you then have the issue of 1 LB in Shaw, his first season and he's suddenly going to need to play virtually every game from the start as we have no backup there whatsoever, unless you count another totally unproven youth player... Reece James. Same applies to RB really, we only have Rafael there who is a naturally good RB.
Going to the Central Midfield.... it's just horrid... virtually every pairing you can give is an unbalanced one apart from Fletcher/Carrick with Herrera possibly, wouldn't want to even think about playing Cleverley/ Anderson or Fellaini as a major role this season, or ever for that matter, they are poor choices as back up if you ask me. We really do lack something here though, a physical/aggressive ball-winning/defensive type midfielder.
Also we have no great wingers so therefore 4-3-3 isn't possible, even LVG admitted this.
Not only are we lacking in key areas - CB, CM and winger/ natural-wing back in particular (we want the option to be able to effectively change systems), we also have a lack of balance with the players we have at the moment. LVG has admitted all this as well.
Maybe you are being overly optimistic about our opening games, because in my mind we will be playing teams who have more of a balance to their squad than we do.