I agree with Swiftus and others that the real challenge right now is maintaining a challenging, competitive and fun environment for all kinds of players, not just those that can, due mostly to personal circumstances, devote enormous amounts of time (and use some dubious techniques) at the very beginning of a gameworld to establish control of a major airport and build a legacy carrier in a few short game years. This dooms the rest of the field to fighting for scraps until the CEOs of the mega-airlines get bored and voluntarily BK, if ever. Something ought to be done to alleviate this even before v.1.3 is released. I think some across-the-board tweaks might be made to help (though not solve) the problem in the next v.1.2 gameworld.
The first problem, I agree, is that the practice of securing every available slot indiscriminately with any kind of available aircraft, has to be financially punished. The only way to do this, I think, is to universally jack-up commonality costs on every additional type, to increase further the costs at the current break points (the 4th a/c etc), and to make engine commonality significant. Even startup airlines in AWS can right now make profits three or more times as high as they would IRL; there is no reason why commonality costs, therefore, cannot also be made multiple times more than they would be IRL or are currently in AWS.
The second problem is slot-capturing (I won't use the dismissive term 'hogging' since, frankly, the structure of the game encourages players to secure slots as quickly as they can, and even players who do not abuse the rules know they have to secure slots to secure market share). Again, the most straightforward way to slow down slot-capturing and push players to choose more appropriate a/c for their slots is to jack-up the price of slots, across the board. In v.1.3 I hope Sami can find a creative way to deal with differential slot costs and flight frequency preference issues, but before then, airline growth and slot usage could be slowed by significant increased slot costs.
No doubt these measures do not help smaller airlines and late start-ups, so third, I suggest (as I have before) that those who start after the initial rush be given more start-up money over and above the general level of inflation. I suggest a formula of the base amount given at the start of the game, plus a certain percentage increase every game month divided by the number of bankruptcies, plus an amount equivalent to the rate of inflation for the previous game year. So, a player might get $4 million at start of game, but a new player starting two months later would get $4 million plus (say, at 5% per month) an additional $400,000, while a player who starts two months into the game after a bankruptcy would get $4 million plus $200,000. A new player who started 2 years into the game would get, $4 million plus $4.8 million (then multiplied by the inflation rate over the two years). A little complicated, I realize, but surely this is possible to code into v.1.2, and it would reflect the fact that in IRL late entrants to the market need more start-up capital to get a foothold, and it would help reduce (though not eliminate, I realize) the possibility of late start-ups being immediately crushed by existing large carriers. {Addition: there ought to be an upper limit, of course, perhaps at 4 or 5 years into the game the increases should be stablized for the remainder of the game}
My two cents. Oh, and I'm in the smallest minority asking for a 1970s start time -- no doubt reflective of my age -- but also because I find that era, with its small airports and slowly building demand, to be the most challenging and therefore rewarding.