I spent the first two years of my coding games working on Match 3.
Not because I thought it was my dream game but because of a lot of practical reasons.
Market research showed that Match 3 was in the top 3 categories of casual games.
It lends itself very well to mobile gaming ; which was the easiest way to get self published.
I thought at the time the programming of the game logic would be easy (not so easy afterall once you start putting in special gems!)
A few of my Match 3 products :
Pirates JewelsHoliday CheerPirate Jewels II .
In the end
it has cost me more money to produce Match3 games than I have made out of them.
In addition to that I have come to realize that if I'm going to spend that long working on games that I really have passion about making rather than things I was doing just because I thought the market would treat me better.
When I'm done making my next game I want to feel that the journey and accomplishment were enough reward even if I'm the only one who ever plays it!
I'm not suggesting that you should not enter match 3 genre. I'm suggesting you review your reasons and make sure that it is what you really want to do because there's an immense amount of competition there and the odds you are going to be King or PopCap is extremely low.
In so far as the mechanics you mentioned I can only suggest you focus on fun and understandable game play. If players find the game play too complex (as with the Pirate Battle mode in Pirates Jewels II) they won't like it. If the game play doesn't progress with difficulty over time they will find it potentially boring.
Best of luck regardless of your decisions.