My feeling is that EB is a good program for you. You managed silver which has a very low threshold and I assume in most other programs you would still be at basic level.
So you can make the best out of it: traveling during summer time or around new year with SAS gets more convenient for you and a fellow pax.

And regarding who is FF and who's not, it always depends on the peer group.

I have a ffp account with an airline I've never flown and most likely never will fly, just because they have good earnings on partner airlines that I fly, a very long point validity and even lifetime status cards that are relatively easy to achieve... I might be a valuable person, but oh my, I'm a lousy customer.

Anyway, I would suggest that OP reads and watches the FAQ of EuroBonus as stated on the site. It can be found here: http://www.sas.no/en/eurobonus/about-eurobonus/

Having a specific time-bound window for qualifying for status is common practice with about 99,9% of all airlines, I think. Also, please note that you earn two types of points (as is common with most airlines) : qualification points, which are valid within the time-bound window for reaching status and extra points, which are valid for 5 years and can be used for bonus flights and other goodies.

Can I recommend another program? It depends on your flight behavior. If you fly most with StarAlliance and specifically SAS, then I think EuroBonus is the best choice. I cannot recommend Miles and More, as it's only useful for people who fly a lot in first and business class with the Lufthansa Group nowadays.

Aegean used to be a bargain for people who don't fly a lot but still wanted to make Gold, but the company has significantly changed its program. Asiana still has a good deal, but only when your fly in the more expensive booking classes. Also, United is most valuable when you fly a lot with them, not so much for partner airlines. All other airlines within StarAlliance have relatively tougher requirements than SAS, especially if you don't (often) fly with them.

Also, keep an eye open for special promotions. SAS had an offer about 2 years ago that would give you a gold card for just 2 round trips in Plus, for example.

Qatar Airways uses a "sliding window" as base for tier levels.

True, but unless you fly QR a lot and in premium cabins, it is not a very attractive program. Also get ready for high amount of protracted retro claims for partner flights. And generally 3 weeks for posting of partner flights....

Well, the QR award program is very good especially for long-haul awards (low taxes and high availability).

But I was just replying to the question regarding a more "fair" way of counting miles towards status