DOOM is an icon. It's a phenomenon. It's one of the best and most important games of all time. It put an entire genre on the map and still holds up today as a classic.
So why is the Steam release so pathetic?
Let's start with small potatoes - the store page. Why? It's just to demonstrate the laziness of the release. Look at the banners. The Ultimate DOOM logo outlined in a black square with words "The original game that set the world afire" and lighter black around them. DOOM II's banner doesn't have a slogan underneath the logo, but the logo is outlined in red and has black around it. How damn lazy is THAT? They couldn't even make a proper Steam banner? It's not rocket science. Let me give you some examples of much better community-made DOOM banners:
http://img.booru.org/steambanners//images/4/5df20109847b5175cd2b8abc20c55346fec5ab8e.png (my personal favorite for TUD)
http://img.booru.org/steambanners//images/4/e32a0d3ba3f1addba4c808f5df296a7e5f505a80.png (my personal favorite for DII)
http://img.booru.org/steambanners//images/4/e6da033011da5cf00341376253e0a63c8215457e.jpg (Dead simple - darkened DOOM II box art and the DOOM logo, yet looks pretty good)
http://img.booru.org/steambanners//images/4/c6282dd0cda6100266154de27c6b19ba873bdcca.jpg
Final DOOM's and Master Levels' banners are okay.
Now, why the screenshots on the Steam store page are scans from the original box? Come on!
Now, that was small potatoes. Let's go to the big ones.
The releases are the original DOS games with DosBox. Which means: no widescreen resolutions, no remappable controls, et cetera. You could say that all those features weren't present in the original releases, but I say that A) The original releases were back in the nineties and now is 2013 the rereleases like the Depth of DOOM collection used Windows ports that supported more stuff. I'm not saying you should go the extra mile and recode the engine to support Win7/8, high res and remap (even though you should), but at least include a source port. ZDOOM did all that and then some.
Even as it is, Dosbox isn't used properly. With current config, the music is butt ugly, almost like 32X DOOM and the vertical mouse movement isn't disabled. Simply editing the config file makes the music much better and using novert.com file before the game disables vertical mouse movement.
Also, as of late, all the colors are funked up under Dosbox, which can also be resolved by using different renderer.
Back to small potatoes: where's the manual? I know it's laughable, but you know what? The manual should be there because it's the only source of the game's story. I want to know why am I in a hangar with nothing but pistol and there are zombies around. Either that or go the extra mile (you won't) by patching in a text promt that explains stuff.

It is kinda pitiful. Never looked at it before. Still all you need are the Doom and Doom2 wads to run any of the modern engines, well and the level wads for that game.

I do hope you can break them out from your Steam install.