The Anko event was incredible. I don't know what the financials were for that event for Wargaming, but if it were possible to do other tanks in GuP with their commanders providing voices then I would be all for that. And certainly the number of Anko's out there suggest there are plenty of players who enjoy theirs as well. Since so many of the Oorai tanks from the series are from those lower mid tiers you aren't really risking suddenly giving someone a high tier tank that they otherwise wouldn't have. Maybe you could even have a mission that grows like the Tankenstein one did. Say first 50 wins unlocks the Lee for example. Then the next 50 gets the StuG or Type 98 and so on through the rest of the tanks.
Tankenstein itself I thought was too much. The targets grew to massive numbers for non-hardcore every possible chance to play players for what is in the end a novelty piece. Yes, you could unlock with Gold, but that basically means the drivers are either Richie Riches who just spent 10k Gold without blinking, or hardcore grinders. It wasn't something that overly interested me, the choice of guns was the big point, but it wasn't really enough for me to want to grind that out.
RoC was fine for what it was. I made sure I qualified for the rewards, and did certainly play my tier 8s a little more. It was good beating NA, but mainly because I lurk in their forums and it was funny seeing them coming up with their excuses why they were losing.
The two race events were OK. I did make sure I qualified for them both. It might well have therefore started those two grinds a little earlier than I might have otherwise, but I like the Japanese lower tiers, so I'm happy with that. And again, with the lowest target NA couldn't manage their samurai one which has led to another bit of amusement as they pretend they are the only server with a real life so it is unfair they should be expected to actually do something for the reward.
The other missions and events like the Hype 59 event and such are fine too in my opinion. If I'm interested in the reward I try to complete the requirements to get in the draw, if not I don't worry much about it. I just never go in thinking I will have a chance to win the ones with most whatever. I don't play enough games per day for those.