I've only been introduced to the TES community recently through playing Oblivion on the '360 and I own all the plug-ins that Bethesda has released so far. Despite enjoying the game itself so much, I regret buying the '360 version after hearing about and seeing all of the mods there are for the PC version. (I'm actually considering getting the PC version myself).
Although not having the privilege to actually use some of the content modders have out, I see what points are being made against Bethesda. In a general sense, many modders, for all kinds of games, put a lot of hard work and dedication into their content, releasing things innovative and beautiful.
On the other hand, Bethesda (and many other companies, actually) put only enough effort into make something innovative and do it to an extent. Afterwards they release it and charge $3. In reality, this is more than a modest price. Honestly, I have no problem at all for them to release content and charge for it, they're a company and like many others, they have to make money in order to proceed to and succeed on other, future ventures. Come to think of it, $3 from every single person who plays Oblivion and purchases content from Bethesda maybe, in the long run, investing in TES:V.
It saddens me, however, to see modders going the extra mile to get players into the true gaming experience while Bethesda, having the resources available to practically rebuild Kvatch, allow adventuring to new lands over the new dungeons they've recently been making, is still staying inside the box by doing only enough to keep people merely interested in the game. Not only that but they’re actually profiting through this. Even if modders see recognition as enough, they certainly deserve more.
This isn't rare at all in other communities, but just not as severe. For example with The Sims 2 Maxis is charging for sets of content like Holiday items and a “Family Fun” theme. There are some original and well-made objects in this content, but it barely compares to what comes out of the community. The difference in this matter is the fact that some of the bigger parts of this community actually require monthly-paid subscriptions for access to chunks of the content they have available, so at least those innovative members of the community get some profit out their great works.
In the end, its just a matter of circumstance. Why does Bethesda do it? Because they have the power to, and they can, and that's a sad truth we all have to accept. Although the modders make such great content its due to Bethesda that there's a game to start with. However, without the modders, I'm pretty sure the fanbase would've died long before the first plug-in.
I think of it this way: Bethesda makes the actual game and the modding community paves the
gaming experience. As we get deeper into the gaming experience, Bethesda makes a quick buck or three by taking advantage of it and releasing mediocre content only to have the modding community eventually build upon that content to get us only deeper. Then Bethesda makes the next Elder Scrolls, we forget about this whole mishab, think about all the good times the gaming experience was (mainly due to the mods xp) but the cycle ends up reoccuring. And, I guess, that's all there is to say about it.
On a lighter, more in-topic note, I actually found Mehrunes' Razor an excellent plug-in in comparison with the others. For $3, that extra dungeon provided a lot of enjoyment. I mean, honestly, what's there to hate?
To start with, you have a whole community to kill off and the only thing to worry about is dying. Just killing everything in itself was enjoyable. Then plundering the buildings was pretty nice, lol. I liked taking books from some buildings just to fill in my own bookcases back at Skingrad. The Morag Tong assassin was probably a nice blast from the past for you MW players. I stumbled into the Commander's building a long time after I freed the guy and saw him getting into a battle with the Commander. It was awkward to see an assassin actually engage in direct combat, so I just gave him a hand and butchered the commander. (Mainly because I needed the thing to open the portal and besides, those daedric greaves on him looked like they could make me a good coin or several.)
Crashing into the battles going on at the Ayleid ruin was real fun. I even had those arrows that did 60 pts. of fire damage in a range of 10 ft. so I had a blast, literally. lol, blowing the vampires to bits while damaging the dunmers a bit was interesting. The vampires seemed to have the upper hand to start with, so finishing off the remaining dunmers wasn't quite a problem.
Simply reading about the story of Dagon's failed champion was quite interesting. Almost as interesting as actually giving the poor guy a second death
after eating his heart and killing the other guy who wanted to overtake the Empire. I even thought of a parody of a line from that Star Wars Rap while doing it.
"Get in front of the Empire, to all you Ocato-haters out there, we'll blow yo village up!" 'xP (well, it sounded funny at first)
The only thing I didn't like was how my infamy went up 4 (from 0, too

) during the quest, I don't even quite remember how. Maybe going around murdering things secretly (100% chameleon is fun) had something to do with it. Actually, I do remember accidentally pickpocketing a few guys while in the village. =p
And the Razor was kinda overhyped. It only randomly kills things in a hit, but hey, I wouldn't want an uber weapon in my hands, makes things less fun.
So, even despite my feelings about the modders not getting what they deserve, I must say Bethesda has shown much signs of improvement in the work they put into plug-ins with how enjoyable Mehrunes' Razor was. Hopefully they can continue this with whatever plug-ins they're planning for the future.