I already have a full version of Strum GS-2. Do I think I'm getting a bit of the short straw? Nope. I think it's awesome, the same way I think that the inclusion of Melodyne Essential is great, even though I have a license for the polyphonic editor.
The fact that SPlat will directly support VIs et. al that I already own was one of the big "selling" points when I looked for a replacement for Studio One (instead of upgrading to v3 and heading into PreSonus' version of Jurassic Park). I had AD2 already, but got to add the 3 each ADpaks, MIDIpaks and Kit pieces. That made the choke-inducing 1 year membership cost tolerable and very competitive with what would have been my upgrade cost for S1 Pro.
And their ARA implementation made Drum Replacer possible, an unbelievable goodie that was totally unexpected.
Also, the joint facts of SONAR's loooong existence and Windows-only DAW line were big selling points. I've been in software development, and some of that time was spent trying to support multiple hardware/OS platforms. I am thrilled to know that all available resources are working on the platform that I own.
So...I like the way this is going! Props!