They always do the tradeoff system (where we get games EU has when they get games we have) for the VC. Always have and always will. If you want someone to blame, blame Dan Adelman. He stated multiple times that one game a week for the VC makes more money than dumping a ton of games at once, as if they do that then folks will all just go for the most popular games, which is what happened for the first year and a half before they changed the plans when Wiiware launched (though personally I thought that was an awful decision since nearly all of the WiiWare library consisted of Shovelware, unlike the Wii U/3DS eShops which get decent indie games often.)

Heck, look at Japan and Europe's VC, since lower sales for non-popular games is EXACTLY what happens over there. All the obscure/non-first party games get barely any activity on their miiverse communities, while the biggest names get the best sales, since Nintendo owners like their first party franchises (which is kinda a reason why third parties avoid the system for newer games). Reggie has gone on record to even mention that the Virtual Console performs the best in North America despite us being slower in releases. Like it or not, this makes Nintendo the most money, so they'll keep doing it.

As for why this week is the exception, I assume it's because Europe has received a ton of games in bulk for the past few months, and if they kept up the one game a week deal over here then we would be behind them without a chance for them to catch up to us. Therefore, I imagine NOA & Konami want to release the Zapper NES trio that Europe has, since they all have the same similar idea and none of them are a big AAA title that would ruin sales for the others. I wouldn't be surprised if they released the Ninja Gaiden NES duo and DDIII for the same reason next week.

The VC could definitely improve, but considering the fact that nobody buys new consoles for old games, there's not much point in doing so, especially if it still makes lots of money for Nintendo in North America. As for the games that EU has that we don't? Well... These are some of those games. They are slowly getting a few games that we have had for a while now (still no SMA1 and SMA2 though), and like always the tradeoff system will continue until eventually we have pretty much the same titles in both regions, before we start separating and getting different games again.

Mark my words, there will be a moment when Europeans will start complaining because we'll get a game that everyone is crazy over like FFVI Advance or Majora's Mask months before EU, yet it'll be inevitable for the same reason.