I replied to a recent announcement post about the removal of the possibility to purchase a specialist hire with neptunium, but didn't realize it was announcement and wouldn't actually post to the forum.
I understand that the effect of that rule change wasn't what the devs were looking for, and in general that there were too many specialists running about in some games. However, in the one game I played with the buying hires rule in effect, this rule was not abused, and in fact seemed to be used sparingly and in situations where time was of the essence. In other words, the players in this game were mature and measured in their use of Np and didn't spam hires or try to get the game to go on forever by purchasing specialists.
I can see how that might happen, but losing the ability to buy a specialist hire removes an interesting and complex decision from the game that I would like to see returned if possible. Devs and players, please let me know if the following idea has merit.
The purchasing of specialist hires increases with each hire by a factor of two. The first bought hire for a player is 20 Np, the second 40, etc. Actually, there's not much more; due to the natural limit of 200 Np ending the game, after the 160 Np hire there would be no more bought hires available. This numerical limit would prevent specialist spam, as would the increasing amount of Np by making the cost-benefit calculation veer more and more to the cost side with each bought hire. This would make a second purchased hire a hard decision and a third or fourth pretty much untenable.
This follows along with the game mechanic of new mines doubling in driller cost each time and limits some of the negative results of buying specialists while still keeping the mechanic available for specific strategies and circumstances.
An alternative but similar idea would have the cost of each hire from the entire pool of players increase each time a hire is purchased, but more gradually. For instance, after the first time any player buys a hire, the cost goes up to 30 Np, and after the second it goes up to 40.