Thank you for the very helpful review. I can tell from these pics that I won't be using the tie-downs (so it's good they're removable). I've been packing clamshell backpacks for years without tie-downs, and don't really think I'm missing much. They don't actually compress the packing cubes (you could get compression cubes if you really wanted that) and in the case of the Synik, anything I want to access will be in an outside pocket anyway, so the security of tying down cubes isn't as important.
Also, strapeez...that's a great idea. I'm going to buy those instead of web dominators (which I have been using for years)...I'm convinced.