To be fair the running out of energy is little different to the 1980s turbos in F1, where they frequently ran out of fuel. Monaco 1982 stands out in particular (and it's regarded as an all-time classic), and Imola was always a fuel-sucker. They used to have to coast and save as much back then (people conveniently forget that too).
No, back then they didn't have the sophisticated data and telemetry they do now, but when some of the smartest people in motorsport miscalculate laps, time and pace the end result can be the same.
In terms of excitement I think Jack Nicholls deserves a lot of credit. Yes he can get over-excited, but his enthusiasm is genuine (unlike ITV-era James Allen or David Croft) and goes a long way to keeping you on the edge of your seat. A good commentator doesn't make a race exciting, but they will keep you enthralled, and Nicholls certainly does that in FE.
I really like the open energy management. I think that other motorsports could benefit from having fuel sensor telemetry available to coverage if they're going to involve fuel saving at all. Instead of being an opaque oddity, it's something fans can understand and engage with and it frequently leads to exciting finishes.
I think it was Mexico City a couple of years ago which showed exactly how the limited power can lead to exciting finishes, where it was no where near as extreme as Valencia, but some cars were struggling on the last lap and Wehrlein lost the lead by running out metres from the line, having to coast while da Costa power-slid around him to grab the win by just two tenths.
Let's face it, Formula E as it is isn't going to be a format long-term. It's a bit of a spot-gap for a decade or two while they work out where the market is going in the future, be it electric, hydrogen, some form of hybrids or whatever. But while it's here it's damn good, and alongside Indycar and F2, is often produces better racing than F1.