Why? I say it again, these reverb effects are phantastic - I never expected them to be so good. But I also have to say, they only sound good if listened through headphones - I also have a 7.1 speaker setup and DS3D and also the EAL reverb effects sound pretty shitty through speakers...
There are different factors. I am currently pretty deep on getting things on rendering straight and I want to focus on that. Then this is an UT only thing, there are no EAL presets for other UE1 games. The Editing tool they used only starts when you own a Creative sound card. I have no idea if they would even work on any recent OS, so we need to implement a way for creating new ones. At least they do have an documentation how to use them with OpenAL though using the EAX extension and not EFX, but that shouldn't be much of a concern.
And for me personal, I favor getting away off custom made preset to either full non preset based audio rendering or at least autogenerate these out of a map and maybe use them a bit like a shadow map. Deus Ex in particular is very interessting for this, because the used texture groups to indicate the footstep sound, so basically for the whole game and custom content there is already pretty much all data in needed for this. Unreal 227 uses an enum in the Texture class to handle similar things. In any case this is a large scale endevour, so this is pushed back a bit.
regarding the sound bug: this problem did NOT exist in the previous version (2.17.000x) of the Creative driver in ANY legacy game (UT99, UT2004, Q3A, etc.) - so it must be related to the new driver version. There are already existing topics on the Creative forums about this issue...
To recap what is the issue. There is no minimum of supported simulatanious playing audio soures required. So they could even implement that unless you use the hint for requesting a certain amount, so always get zero simulatanious playing audio sources, e.g. no audio playback at all. This would still be not a bug on Creatives side, but a perfect (though unresoable) valid behaviour of an OpenAL implementation. Maybe they just decreased the by default minimum supported amount of simultanious playing sound source in their application, or had some compat code in, to always allow new sources and they just dropped that. So arguing that this is a bug in the driver while there are obvious bugs in the applications which would exactly explain this behaviour is unresonable. So I just checked the binary of UT2004, they don't supply the hints at context creation, nor do they query the limits. So exactly the same bug in UT2004.
However what you can try in case of UT2004, in my UT2004.ini there is a "Channels" setting. I don't know whether this is used but you should try some low values starting off 1, 2, 4, 8... and see if it works before (though most sounds will be outruled using these low settings anyway) and see where it starts to break.