Having read the sentiment in the forums against spamlines, I have a modest proposal on one way to control their pervasiveness.
I know AE already has a "One Hub/Terminal Limit" game as a special world.
Expanding on this idea into the "what's realistic" mindset, perhaps there should be a maximum number of hubs allowed in "realistic worlds" games that is maybe the number of hubs of the largest airline in the real world, plus one or two? Looking at some of the largest carriers in the world, United for example has hubs (at least in the home country) of IAD, EWR, ORD, DEN, IAH, SFO, LAX and GUM (remember, GUM is a US Territory!). AmericanAirlines' home country hubs (post-merger with US), are PHL, MIA, CLT, ORD, DFW, PHX, LAX and DCA. So maybe cap airlines in realistic worlds at 9 hubs in the home country?
So often when I run into spamlines and look them up under the rankings they have like 25 hubs. Not very realistic.
I only recommend this for "realistic" worlds as "open" worlds are supposed to allow things like this.
What does everyone think?