I'm not familiar with idine. Any 15% cashback deal is exceptional.

In general here's what I would recommend:

There are 7 cards worth "churning" - that is, getting, meeting the minimum spend requirement for the signup bonus, then abandoning after the first-year fee waiver expires. These would be:

Amex Preferred Rewards Gold
Amex Gold Business
Chase Sapphire Preferred
Delta Skymiles (gold or platinum)
Citibank AAdvantage card (get two)
USAir Barclay's Mastercard
United Mileage Plus Explorer
(Some might also add Chase Ink Bold)

You should each get each of these cards, and read through the forums to make sure you get the best signup deals. Getting the best signup deals is an important part of the process. Also, look at the spending requirements and time/spread out your applications so that you can meet them. There are also threads about how to increase your spending (see Serve, Amazon Payments, and Getting Up Spending Without The Mint).

If you cycle through all these cards, you should be able to accumulate about a million points in a couple of years. That's the good news.

The bad news is that your points will be spread across the three main airline alliances, and you will have trouble accumulating enough points on any one of them for three tickets, especially if you want to travel business class. The other bad news is that even once you have the points, you will have to find availability. My experience is that you can find it, you just have to be somewhat flexible, but more importantly, you have to know the tricks of how to search. (Just as one example, the difference between flying from Raleigh (where I live) to Europe and back in business class can be 80,000 miles depending on whether you fly coach or first class on one leg of the trip between Atlanta and Raleigh - and the Delta website will not give you any hint at all that you can save 80,000 miles just by downgrading for one hour!)

But with some research on this site, and carefully managing your spending, yes you can accumulate a lot of points, and if you don't get enough, just reapply for the cards a couple of years after you cancelled them.