Would have been cool to see a successor (or the Vita itself) developed with the kind of end-user & developer philosophy the PS4 was based on. I feel like the lack of demand is not simply the absence of a market, but also the inability of Sony to create demand as a result of numerous factors, not least of which the obstructive pricing model of memory and the marketing-driven idea that the Vita needs/will have graphics on par with traditional consoles, but neglecting the associated development costs that necessitate strong sales/extensive marketing. By effectively ostracizing mainstream mid-tier games and relying on a volatile model like this, it's no surprise that it became such a polarized platform in the development field -- anything new is either indie or caters to a small, but consistently supportive niche market. The most illustrative case is probably when Sony shat out stuff like PSABR and some other (decent) first-party content that was dead on arrival because they didn't care enough to tell anyone it was coming out.
Sony should have been upfront about giving zero fucks about the Vita's future, so at least everyone was on the same page and we wouldn't have seen good studios fall apart because they actually believed in the platform. What's equally unfortunate is that they kind of poisoned the well on handheld gaming in general. I think their Vita policies can only be described as 'impressively bad'.
Also, an OLED screen susceptible to burn-in on video game platform? Clever. Honestly, it all makes more sense if this was some kind of elaborate, evil ruse.