You're mostly right, but...
Dynamic shadows are still present. You can easily see this on the shadows underneath e.g Sentry Bots or Trites. What was removed was certain lights casting shadows (see the "Flashlight shadows do look like ass" thread for an ongoing discussion of this), but it's incorrect and misleading to say that all dynamic shadows were removed.
I haven't done any measured comparison of texture resolution but to me they look the same. What is different is that BFG edition uses texture compression which was not used by Ultra mode in the old version. This has the unfortunate side-effect of adding compression artefacts to the images, which in some cases are extremely visible, and which was one of the more bizarre decisions made for this reissue. All the more so on account of the fact that the new asset packaging system has hugely bloated the install size.
Unfortunately a patch with uncompressed textures would be a > 7gb download; not impossible for some but highly unlikely to ever happen.
A patch with increased texture resolution is just an unreasonable demand - you're effectively asking id's artists to remake every single texture in the game.
Your best bet if you want increased texture fidelity from BFG edition is to wait until the GPL source code release happens and pester some folks to add support for the original games textures to it. Cold comfort I know, but that's just the way it is.