Right, but for one thing, if you take that to extremes it will gimp your character so much you could very easily die without finishing that last 5%, and with repair costs that definitely is a deal breaker.
My MF suit doesn't leave me gimp, each piece has ~100 Int on it and a couple of them have IAS/Crit/Vit, etc, while having max or close to max MF. Worst case scenario, I die once, which will only incur repair costs for my MF suit, which would probably be in the realm of 500-1000 gold for 10%. Not a big deal. Try again.
Second, i suspect utilities that due this are within the realm of what blizzard may consider bannable. Thats certainly not a given, but its definitely a risk.
Doesn't appear to be. People have been using macros to gear swap from the first week and have been doing so on practically every stream out there, none of them have been banned for it.
Third, theyve already said they disagree philosophically with swapping MF gear for killing blows and will be looking at ways of disincentivizing without changing the effectiveness of the stat itself and people who are using it "legitimately"
They already did, by making it not work on chests/breakables. If you only use gear that Blizzard might not change in the future then you can't use any gear at all, can you? Most pieces of an MF gear suit can be had for ~200k. It isn't a large investment. You get a couple of good drops you wouldn't have otherwise in a few hours of play and you've already paid for it.
Fourth, it takes up precious inentory space that means you have to make more frwuent trips to town to salvage / sell, further reducing efficiency.
I can town portal from just about anywhere in the game. An extra 20 seconds now and then to dump rares into my stash isn't a problem.
Fifth, you can use MF gear when killing trash packs and see substantially better drops this way, which you wont get from gear swapping unless you plan to do this for every single trash enemy you ever kill.
Trash mobs aren't guaranteed drops. The only reason to kill trash mobs at this point in time is if you are wearing a full suit of Gold Find gear. Everybody else who knows what they're doing is just running from elite pack to elite pack, skipping all the trash---if they have a class/build capable of doing so.
Sixth, the enemies you actually do bother to swap on (bosses, etc) have a large portion of their valuables guaranteed. So percentage wise you arent looking at a huge increase in rares over not using MF.
Wrong, unless your idea of "large" is one drop out of 10-15. The simple fact that these bosses drop so many blues is one of the BEST reasons to have an MF suit in the first place. Why kill the boss and get 1 rare and 6 blues when you can kill him and get 4 rares and 4-6 blues?
This is why using actual good gear will always be more effective, more efficient, and more expensive than poor man gear swaps.
Undoubtedly having max magic find on your max dps/mitigation gear is the best option, if, IF
a) you can find the pieces in question, and more importantly
b) afford them
I can't find them regularly and when I can I don't see any reason to pay millions for them when my cheap MF suit is just a ctrl-R away.
In the meantime I'll keep my magic find suit in the bottom of my inventory, ready to swap in as needed and keep my eye open for replacement pieces with high MF for my main suit that don't cost a fortune.