No disrespect intended, but if anyone is suggesting that development timers will be an inconvenient wait because of the microtransactions, then I doubt that those people played Peace Walker. (If you have, apologies, but I don't know what to tell you.) In Peace Walker, weapons and items progressed as you completed missions in the field. The further you got into the game, and the more advanced the research became, the longer it took to develop. This would take an ungodly amount of time. Like, for example, I can't remember which item (maybe the Fulton Carl Gustav), I had to complete about ten of the 5-Skull difficulty missions. I can almost guarantee you that MGSV was going to be super-grindy regardless of microtransactions. Peace Walker really rewarded you for spending a great deal of time with Mother Base and the development of the base as well as weapons and items. I have no doubt that they had the same intentions in mind when they made this game - even after the implementation of microtransactions. Ignoring Mother Base will be impossible in this game, if I had to guess, as self-inflicted pacing issues will arise to those who choose to ignore (as one previewer pointed out with his experience). More so, a roadblock will be hit, whether it comes to bite you in the butt in the first Act or 75% of the way through the game. This happened to a good number of people who ignored it in Peace Walker as well, with the first big roadblock likely being the Pupa fight. They said during the presentation that as important as completing missions in their field is, it is equally important to spend time with Mother Base. Yes, it is a grind. It is supposed to be. You don't build an offshore military base overnight... unless you pay up. ;-) Kidding aside, one thing that isn't being talked about is that weapons/items will have a shorter development time the higher the rank of the unit developing, if Peace Walker is anything to go by. (One would assume that this is still the case.) Also, worth noting that certain items are disabled during FOB gameplay, so there's that too.
But as NoctisVsStar pointed out, for those concerned about 1-v-1 gameplay being affected by microtransactions, the FOB system is completely optional. If you're that worried about people tearing apart your base with microtransactions then
tbh
You're going to run into people who have spent a great deal of time and effort developing and you're going to run into people who have swiped dat credit card in hopes of a shorter in-game development time for the weapons and items they look forward to using, and the truth is, the difference between the two will be dependent on how skilled each player under the given circumstances is, because at the end of the day, that is what will matter most. If you are looking at strictly the loadouts of each player, then yes, there won't be much of a difference, however, there is a reason that the games are played and not simulated through how advanced the gadgets the players acquire are. There will be people with more advanced weapons and items than others, no doubt, but does that make them a sure-fire winner? Not at all.
So can you construct the exact layout of the bases (MB and FOB)? Or is it all randomized or pre-set.
I'm guessing that the buildings themselves are preset given that indoors are accessible, however, the placement of struts and the security (patrols, cameras, turrets, drones, etc.) will be entirely up to the player. When the Diamond Dogs soldier is selected and is out on a mission in Africa, they touch on this a bit, stating that players can get really in-depth with their defenses.