Be careful of reading too much into that. If you have an issue you're gonna come online and speak about it. There will still be a QA failure rate on even an 'updated' motor.
That Jan 2020 date is not correct according to Specialized they have been doing running upgrades since the motor was brought in. According to them, and I am only passing on what I've been told, Jan 2020 wasn't a magic date.
All motors suffer a percentage failure rate. The important thing is how fast will the bike be turned around. I have 5 mates with Bosch motors. 3 have now had issues resulting in a dealer visit. One is now without the bike for 10-14 days whilst the motor goes back to Bosch.
Shimano have been the same, one mate still no bike after a month nor a fix date.
@R120 was also without his for some time.
I think the thing is to get one from a LBS with motor stock that you trust. Berkshire get you back on the trail same day in most cases. We are very fortunate to have Berkshire Cycles on our doorstep who are probably the world leaders in terms of customer support for Specialized.
I don't know what your LBS is like, but ask them if they hold motors and batteries in stock and it will give you an idea of how big a Specialized customer they are. If they are pushing only a few out the door along with other brands I would say you're going to be waiting with any issue with them which will affect your customer experience. But this comes down to the spares they are willing to invest in to support the brand. There are motors available in stock from HQ. With Bosch and Shimano LBS' can't hold spares as the motor has to go back. Specialized actually trust dealers to replace motors in order to get you back out riding, which to me is the reason I still stick with them despite other bikes I've ridden suiting me better..I know the feeling when the bike fails you hate the brand, the bike and feel cheated.
It shouldn't happen but it does and if you want the total awesomeness of this sport then, at present, to me you have to accept a small risk of failure. But I know it will get sorted ASAP..And Specialized aren't going to argue with me over semantics. They get the job done and honour their warranty. The Mahle/Spesh motor seems bombproof and I've not read a single failure so I am sure the issues have been taken on board. The question is do you want FF with that small risk or the SL, less power and a bombproof engine.
My experience is Spesh don't take your cash and leave you out in the cold. They are 100% on your side. You pay a premium for the brand and the warranty but I've used it three times now and it's been painless. One issue was, truth be told, my fault..They could have said bugger off, but they didn't.
You may or may not have an issue, but two of my good riding mates left Specialized due to reliability and have had the same experience shifting to another brand in defiance. One is now back on a Spesh.
You'll probably have a niggle with any brand, it's about how fast that gets fixed and with how much fuss..