Personally, i think McFarlane's DC Multiverse line is pretty cool. yes, it is very bat-centric, but what else would one expect? McFarlane toys is tiny compared to Hasbro and Mattel, and its the 1st year of the line so Todd needs to make a big splash, and Bats is far and away DC's most popular character. There are with plenty of bat-collectors who will shell out for another variant costume/alt world versions, but could care less about most of the remainder of the DC universe, so producing loads of Bat-related figures was Todd's best bet.
But hey, he made a classic Supes right off the bat (no pun intended), a classic-ish WW in support of the movie, and now a Flash figure is coming, so its not like he's entirely ignoring the rest of the DC stable. I would expect he will cover a wider range of characters in 2021, although he will likely continue to play to his strengths (90's influenced/ "extreme" versions of characters) while producing the minimum number of live action movie/tv characters to appease WB (let's face it, doing realistic faces a la mcu Marvel Legends or Star Wars Black Series is not his strength).
Collectors had a chance to get a more diverse roster of characters with Mattel's DC Multiverse, but that flopped. Why it flopped is subject to debate, and certainly the line improved as it went on but too little too late. For Skyvolt 2000, well Mattel did make a CW Black Lightning figure, you can still get him for about 20% below msrp on amazon, so i don't take that as a sign that there is huge demand for him. I would posit that Jessica Cruz was hard to find not because she's super popular but because she was single-packed in the case and the wave had a sought-after Build-A-Figure (Clayface), plus Walmart had seemingly abandoned the line by that point aside from movie waves. Two-face from that wave was similarly hard to get for msrp and you're not going to convince me that that particular version of the character was really popular, just that he had a Clayface BAF piece people wanted.
As for why mattel's DC multiverse didn't do well, some potential reasons:
- poor selection of characters in the early wave that led to a lot of pegwarmers such as DKR armored Bats, DKR mutant leader, prison Lex Luthor
-Snyder and Ayers making DC movies that were not particularly kid-friendly the way the mcu movies were
-mattel always seemingly behind hasbro when it came to articulation and quality of figures
-insistence on covering new versions of costumes for characters, many of which were unappealing and often out of date by the time the figure came out
We got lucky with McFarlane's Superman on that last point as the Action Figure 1000 costume was very close to classic looking.
personally, i also like the Hellbat figure and Azrael, even though i can take or leave Batman overall. Definitely plan to get the Doomsday-style Batman figure though.