While I don't entirely agree with your suggestion regarding adding a year-long timer to starting merc contracts, I do agree that this newly added system is definitely lacking... sophistication. Like a lack of a concept of futures "contracts" included in the system seems an oversight. By futures contract, I'm referring to a player's ability to basically pay a premium for a merc to most likely still remain available as of some later date, but sometimes they aren't.
So you can either drag the merc around now and pay full freight while always attached to a ship, but if you pay the premium, you can mostly guarantee a merc's later availability (either by blocks of months, like next 6 or 12 or 24, or up through a specific date). However, the premium cost to guarantee almost certain availability goes up over time, while simultaneously the likelihood of the merc not being available ALSO rises. So basically the percent rate of the merc cutting and running with the contract monies increases with the length of the contract's time. Thus, if you want to make sure you can still hire a merc for the next 6 months, there is a reasonable cost of like 65,000 to "guarantee" availability for hiring (and still pay full contract cost upon hiring), but like a 7% chance the merc will welch on the contract. Conversely, it would cost 500,000 to "guarantee" a mere's availability for up to 24 months, with a whopping 28% chance the merc will renege.
Plus, this would add the story option of later fighting the same merc who welched on the contract and are instead protecting someone else (extra story points if the merc is attached to a pirate fleet you are hunting, although this might require factionalizing the merc system so that mercs from pirate ports are more likely to be attached to pirate fleets while regular mercs mostly instead are attached to merchant fleets, or maybe even took a commission?). Would also be cool of merc's could also be commissioned, so that sometimes if you hire a merc and attack the faction the merc is commissioned for, they either refuse to fight or maybe even fight in space battle against you...
Finally, you can also pay more cash to make the merc available to be summoned to start their contract so long as you have enough cash to settle normal contract length cost when summoning (maybe within some set range of the merc's "home" planet), otherwise you have to still fly all the way to the merc's home planet to pick up the merc (and maybe waste some amount of time flying to merc's planet). Alternatively, game could just also have an option for paying another premium to have merc fly to you (so it might only cost an additional 35,000 to have merc fly up to 10 light years to meet you, 135,000 for 50 light years, 250,000 for entire sector, or default market cost of fuel and supplies plus 25% but if there is a shortage of fuel or supplies on merc's "home" planet, you have to be able to pony up front way waaaay more cash).
Edit: forgot to add paragraph about summoning merc clause in contract.
Edit #2: Whoops!
