http://www.rebelscum.com/TVC61BobaProto.asp
Other than Trooper31 saying it showed up in Germany, it was a Mail In Exclusive. Anyone could have gotten it if they had 5 viable UPC Codes, $6.99 for shipping/handling, and the redemption certificate.
The difficulty would only arise if one lived in a country that perhaps couldn't participate in the mail in procedure, or if one didn't want to buy five other figures and cut off the UPC codes.
The people that aren't excited about it seem to feel to some degree that re-releasing it dilutes what made it special as a mail in exclusive and/or part of the Vintage Collection.
Now if you had the TVC one loose and there are no paint differences, then yes you would have put more money into getting the TVC one.
And perhaps if you wanted to trade/sell the TVC one, if someone isn't interested in it carded, then they may just as well try to get the new version, so those TVC ones may go down in value.
So those are some reasons why some people may not be excited for its re-release (aside from wasting a slot for a different figure).
However, If you have a carded version, I don't see this as ruining or lessening its uniqueness or special nature. Because you had to have had the original TVC one to get the card. It remains special in that aspect. You can have an army of a dozen Black Series loose ones, but that isn't the same as having a carded TVC one. It might burn up those who spent lots of money to build an army of TVC ones, but I would almost think that there are less people who did that, than people who will buy up multiples today of the BS one. This provides collectors a chance to get multiples (or just their first one) which is good for collectors in general, but doesn't dilute the special nature of the carded TVC one that others already have.
While not exactly the same, the TVC ERG was an online exclusive. Because of that, many people never got one. When the ERG appeared in the BS, I seem to recall people buying them up in multiples and generally being happy to get a chance at a figure they never got before, and in multiples.
The same for Ahsoka Tano, though I believe there were some differences in facial paint apps, and a date stamp.
Again, an online exclusive is not directly equal to a mail in exclusive, but they are a similar concept. It would seem to me that the feelings/opinions would be closer to the same for both situations.
I don't know that I will, but I know that I may consider buying one or some of this re-release, whereas I wouldn't have bought up multiples of the TVC mail in. It's cheaper this way. I guess time will tell but I think there's a market out there where they will sell and not pile up in stores.
I think the limited nature of offerings has reduced collectors to where many re-releases will be viewed as a mistake, that a different figure should have been done. With so few choices, everybody is gonna have a top 5 that they are weighing against the selection and would prefer instead. It's a numbers game now, too few releases won't hit high enough up on enough collectors' lists.
) on packaging. 
