I actually support both the payment for mods AND the 75% cut for Bethesda/Steam.
For the mods themselves, they are giving their programming, artistic, and other such skills to you, the player. From what I have seen of some mods, they are far more than what we otherwise pay for DLC. Quite frankly, I feel it is almost criminal that mods HAVE NOT been paid so far for all of the great content they provide for users. The fear that mods are going to use this as a "quick cash grab" are fairly baseless. I would like to note that no game on earth is "held accountable" for fixing their buggy game on release. Game makers like Bethesda or Activision or whatever choose to patch their games because if they do not, then consumers will 1. return the product and 2. not buy this product, or any other product made by this provider in the future. If I'm a modder, I want you to sing my name from the mountain tops, and if my Skyrim Anime Hair mod has a glitch or two, I feel many mods would patch the mod so that people would continue purchasing my mod instead of watching people never purchase my mod again.
As for the second issue, the 75% cut for Bethesda/Steam/w.e, let's remind ourselves that modders are using Bethesda's base game to make their own mod. Some mods go further than others in modifying the game, but they are still using Skyrim's base game. Definitely improved, but they are using the work of a company who put alot of money into this title. Let us remember that companies are legally obligated to make as much profit as they can for their shareholders, not to provide us with hours of additional free content or to let modders make huge profits.
Modders can continue making mods for free if they so choose. Fans can choose to only download free mods. Modders can continue soliciting donations alone, but quite frankly that donate button has always been there and wasn't getting alot of clicks. Are there drawbacks to this? Yes, especially for the consumer, but at the same time, I do think that some mods are making content that they deserve to get paid for. At this point it is up to you on what mods you are willing to pay for, what sounds good and interesting, and what has good reviews. And, if at the end of the day the modders decide to take their talents and make their own new games because they aren't satisfied with their 25% cut, then that may be a major boon for independent gaming. Or maybe we'll see some really high quality mods so they can get more people willing to pay higher prices
You never expected video games for free in the first place, why should modders continue working for free and only "positive feedback" if they can actually make some good money for their good work?