The "tensor" logic wouldn't be all that difficult to add as a modification. It's technically already possible with DPP, but could be more optimal. It would require a few more fixed swizzle patterns to accommodate varying non-standard matrix dimensions which are simple logic operations. The heavier modification would be getting accumulators working in parallel with the FMADs and a forwarding network to really increase FLOPs. Not difficult or absolutely necessary, but a deviation from Vega. Even that latter step could be hacked in, but likely not as efficiently as properly integrating the operations. Think output to LDS, then dedicated, parallel adders read from LDS. As opposed to connecting the output to input directly with parallel execution. Some patents mention a per SIMD LDS which could be the front end of that operation. From there it's just a matter of accumulators. Not overly useful for graphics beyond downsampling or perhaps prefix sum.
The GF CEO in that article said they had returned silicon to Tesla. So Navi would be close to taping out if that were the case. Modified Vega makes more sense and bulking up on tensor FLOPs isn't difficult. AMD could probably create a Epyc backplane with 4-8 GPUs for processing power cheaper than Nvidia's offerings. More devices for redundancy isn't necessarily a bad thing either. However, if Tesla is keeping the design in house it's difficult to see Zen being used. On the other hand it would make software development more straightforward.
As mentioned above the "AI" hardware is very straightforward. It's giant arrayed FMA operations that are essentially SIMDs with forwarding networks. Precision is only relevant to performance. With LLVM the coding would fall to any suitable programming language as a front end. So C, Python, Rust, C#(this can't possibly end well), etc. Audio mixing and AI acceleration on a PC is probably warranted beyond just game development. It's not inconceivable to be using voice commands/interaction on a PC in the near future considering all the home assistants hitting the market.