What if V9938 never existed?

even with the limitations of 9958, if it had left in 1985 instead of 9938, it would have meant a huge change of scene.
even if the yjk (sc12) had been removed, and the sc8 had been converted into (256x212x64colors of the palette) we would have already had a system that, in 1985 would have an omnidirectional scroll, in BITMAP mode.
even with the system of sprites so strange, that scroll would have been a revolution in the computer scene.
Anyway, I think that another improvement that could have changed the 9938 is that if the sc4 instead of 2 colors for every 8 px per pattern, it would have had a mode like that of the nes, that is 4 colors (3 + 1) colors per 8 px, it would also have been a very important change.

Unfortunately both in v9958 and v9938, the table of sprite visible on the screen is always the number 32 as maximum!
Therefore I don't find anything important with the "clone" sprites of tms9928a, v9938, v9958 ....
Bye bye
DanySoft

There were several limitations in MSX standard from the start. These are:

- MSX1 was based on VDP TMS9918 in 1983. TMS9918 was introduced in 1979 and there were more advanced VDP in 1983. For that age, TMS9918 was obsolete yet.

- MSX1 design had some flaw points. MSX expansion bus doesn't have Z80 Bus Request and Bus Acknowledge signals. These signals are requiere for DMA access. MSX designers chosed a 50 pins connector perhaps because this connector was cheaper than longer connectors. There were not enough pins for all Z80 signals (Z80 has 40 pins), slots, subslots, audio signal, etc. with a 50 pins connector. MSX standard never supported DMA!!! That's a big mistake! VDP and audio devices weren't able to access to CPU RAM without CPU intervention. That is a big bottleneck. Amiga used 40 DMA channels in 1985. This topic was discussed in this forum many years ago.

- MSX2 was a non finished machine (with V9938 VDP without horizontal scroll) when released because Commodore and Atari had already introduced new computers in 1985 and ASCII corporation had to give some alternative computer.

- Yamaha engineers were more interested in making good VDP designs for consoles than good VDP designs for MSX. Perhaps Sega paid them better than ASCII corp.

The sprites support of V9938 and V9958 was very limited. They only supported a bank of 32 sprites and 8 sprites with just 1 color plus transparency per sprite on same scanline. If you want sprites with 3 colors per scanline, you have to draw overlapped sprites with OR effect. With this, MSX2 and MSX2+ can only put 4 sprites (4 pairs of sprites) with 3 colors plus transparency on same scanline. On the other hand, a bank of 32 16x16 sprites is too short without flip x or y.

- For me, this is the main reason. MSX2 was released in 1985 and it was based on Z80. MSX2 should have been based on the succesor, the Z800, but Zilog released late (in 1985) and with poor tech specs. ASCII corporation wasn't able to design a 16 bit computer on time because Z800 wasn't available. If you want to release a computer based on Z800 in 1985 you need Z800 available a few years before.

Z800 was able to manage larger quantities of memory than Z80 (upto 16MB), but Z800 performance was similar to Z80. That's the reason of R800 existence. ASCII corporation wanted a quicker CPU.

Large applications require managing large quantities of memory. MSX Z80 can manage more than 64KBytes of memory by memory page swapping, but this method is slow and it has many drawbacks. If you make visible a memory page above 64KBytes of main RAM, you will have to loose the visibility of one of the current memory pages. This is a very big problem if you are programming large aplication with large and complex data structures. In fact, as far as I know, there isn't any C compiler for MSX that produces code that manages more than 64 KBytes of data and code. The development of such C compiler would be very complex and the code produced would be very slow.

Computers based on Motorola 68000 didn't have these kind of problems, and MC68000 had many succesors. Atari and Commodore paid a a little price, because ST and Amiga didn't have compatibility with 8bits systems, but the benefits were great from the point of view of development.

MSX standard couldn't change CPU because to do this would have been to destroy the MSX standard.

Wikipedia says that Z800 was released late because Zilog was most interested in the succesor of Z8000, the Z80000. Z8000 was an alternative CPU to Motorola 68000 and Zilog wanted to conquest servers market, but the main income of Zilog was Z80 solds. It was a very risky decision.

Anyway, the destiny of MSX had been the same. Perhaps MSX was a little bit longer. Its competitors didn't last much more.

I write this text extracted of Wikipedia:
https://en.wikipedia.org/wiki/MSX#Evolution

"Evolution
MSX spawned four generations: MSX (1983), MSX2 (1985),[14] MSX2+ (1988), and MSX TurboR (1990). The first three were 8-bit computers based on the Z80 microprocessor, while the MSX TurboR was based on a custom 16-bit R800 microprocessor developed by ASCII Corporation. By the time the MSX TurboR standard was announced in 1990, only Panasonic was manufacturing MSX computers. Its initial model FS-A1ST met with moderate success, but the upgraded model FS-A1GT introduced in 1991 sold poorly due to its high retail cost of 99800 yen. Production of the TurboR ended in 1993 when Panasonic decided to focus on the release of 3DO.[citation needed]
The MSX3 was scheduled for market in 1990. Delays in the development of its VDP—then named V9978 on the pre-release spec sheets—caused Yamaha to miss its time to market deadline.[15] In its place, an improved MSX2+ was released as the MSX TurboR; features of the new R800 processor such as DMA and 24-bit addressing were disabled. The VDP was eventually delivered two years after its planned deadline, by which time the market had moved on. In an attempt to reduce its financial loss, Yamaha stripped nearly all V9958 compatibility and marketed the resulting V9990 E-VDP III as a video-chipset for PC VGA graphic cards, with moderate success. Sony also employed the V7040 RGB encoder chip on many other products. MSX-FAN Magazine also mentions the impressive power of the V9990, being able to compete with much more expensive hardware such as Sharp's X68000. "

About CP/M, this video of 8 bits guy about Commodore 128 says that CP/M OS was dead in 1985. See the video between 22min44s and 23min11s. About MS-DOS, was MSX2 a MS-DOS compatible?
https://www.youtube.com/watch?v=wzMsgnnDIRE

Excluding the VIC-II can you mention some more advanced VDP providing sprites/scroll abilities and other similar features?
I think there is no much choice as proved by contemporary computer design.
ZX Spectrum had it's own hw (ULA)
Amstrad CPC relied on MC6845 that i can hardly consider a better VDP than TMS. The major drawback in VDP is the absence of hw scrolling. Even the sprites, as limited they were is a less limiting factor than hw support for scrolling.

Please consider that the VIC-II had sprites (more advanced) like VDP because the idea of sprites was borrowed from TMS as said by a commodore VIC-II designer.