Short answer. No. Yes.
Yes, you can control the order of events in side a single action block, just place the commands in the order that you want them done.
Top to bottom, that will be the order the commands are done.
Cut/copy and paste work just fine to shuffle things around.
There is no hard limit to the number of commands in a single action block. I personally have had over 1000 in one block.
So there is no need to have a string of actions blocks for any reason other than debugging is often easier if you break them up.
Remember, there is no way to put a break point in the middle of an action block, so if you do need to debug, you need to step into the block and grind your way through all the actions.
It really comes down to how you like to lay things out and if the 'specific sequence' you mention is easy to debug in one block or not.
So now you can see why the answer really is yes and yes. Yes, you can control the order, its top to bottom and yes, its better ot use multiple blocks, its a lot easier to debug.
[Note, this answer / question is really one of programming style, if you use OptoScript or program in a different style, you may have a different take on it (but the commands are still executed from top to bottom)]