To be perfectly frank, Dark Game SDK isn't aimed at the DarkBASIC Professional nitché.
Which I hate to break it to most of you, but you are part of that little group..
90% of people around here will never create anything with DarkBASIC Professional, let alone go on to retail it.
Currently you can purchase the Freeware License version of DGSDK for $54 / €40 / £29, if you look at the current prices that means your getting DarkBASIC Professional's Engine for around Half-Price.
While this will mean that people will have to change from DarkBASIC Professional to Visual C++ 6.0/2003 in order to utilise it, fact remains that if you had the know how to actually make use of this SDK you would already have the tools at your disposal.
I know that sounds a bit harsh, but most of the developers who are going to be going for thier will already be using those languages to develop thier Third Party Commands and alike.
The SDK frees these people to utilise a language they are comfortable with. While the difference in speed is VERY noticeable, and people are right, there should be something done to the DarkBASIC Professional Compiler.. I think you should look at this as a chance to push for that to happen rather than complaining about the price of upgrading to a pipeline your not yet ready to use.
Even with Dark Game SDK, learning C++ proficiently enough to actually make use of it will *still* be quite challenging.
As for the Commerical Product applications outside of games. I would recommend reserving your comments until you see the EULA for the Commerial License.. That license is likely to be quite alot higher priced, but at the same time give you more freedom over what you use the engine for.
While IanM's interface comming down is a blow to those trying to work on 3rd Party Tools for DarkBASIC Professional, until TGC change the EULA that comes with DarkBASIC Professional, there is nothing preventing you from creating your own interfaces.
Also while I am personally a little miffed about the fact that TPC Developers appear to be left in the lurch here at the moment, hopefully the DarkSDK (TPCSDK) will be extended to provide you with what you require.
As for 3rd Party DLLs with Dark Game SDK.. yeah not to be funny but what exactly is going to prevent you from using them?
You can use a Dependancy Walker to find out which DLLs are required and package them with your program, then simply call the DLL.
Or you can even create a library which allows C++ to determine the dependancies you'll need, and let it do all the work for you.
The way I see it TPC DLLs shouldn't be a problem, further more with Direct Access to DirectX along-side the DarkBASIC Engine.. it actually frees developers up not to rely on others code.
Newton for example, sure Walaber's DLL is cool.. but you can just as easily use the C++ version of the NewtonSDK. It's free, so there really is no excuse. You need the Advanced Terrain, quite honestly TGCs isn't exactly upto par with what is out there (no offense).
You can quite easily goto GameDev.Net and look up the Whitepaper on Geo-MipMapping. It explains in quite alot of detail how to create Terrain alot better than that in the Advanced Terrain.
For a C++ the Engine you use is just the tip of the iceberg, it isn't the be-all-and-end-all that a BASIC developer has; because you have no restrictions using other Libraries.
The language is more defined and you have more freedom to do as you please, not to mention there is far more resource available to you; often for free.
If you want to try and alternative in C++ then do so.. there are plenty of engines to choose from.
Ogre3D is free for Freeware. Torque 1.0 is free for Freeware.
That is the beauty of C++, there is alot of choice. No one is forcing you to use C++ or Dark Game SDK. If you want to get similar results in DBP though (personally is what I'd prefer), then I'd suggest you start making a petition about upgrading the compiler next rather than the engine!