If you own and like the MMS, keep the MMS. The MMS was my second HT figure and I've still yet to upgrade it. When set it next to a DX02 or DX12, yes, I would use the word "awful." When displayed on its own or next to other characters besides Batman, he still looks good to this day. The figure has virtually zero quality control problems as far as I know. You do not want to get the DX02. The body has a leaking rubber body on a lot of them and you risk getting a faulty product at ridiculous prices. If you feel the need to upgrade, go with the DX12. But again, once you feel the need to upgrade everytime, you're going to be doing a lot of selling and buying.
Solution: Don't buy something that doesn't pass your standards of excellence. Don't let the nitpicking posts of others here ruin your appreciation for any figures you have that you like. If you fall into this mindset, you'll be priced out of this hobby so quickly by buying duplicate characters, custom heads, custom clothes, custom paintjobs, etc. If deluxe ones are released down the road with cool accessories, you can always buy those individual accessories from members here, online stores, or eBay.
By the way, I own the MMS TDK and have never contemplated upgrading it. Like I said, when all lined up, the flaws are more than apparent. But on its own, it gets the job more than done as far as I'm concerned