the sad part is that time increase was post to Nerf the spam but it doesn't even touch it.  what causes the spam is low rps multiplied by bases. 

getting reserves increase rps.  Rps is just ration of cost/ build time.  Build time = to unit strength.   higher build times is usually given to strong units while low build time is given to weak units.     Rps cost per build time or cost per strength of unit.  What ever way you want to look at it.    Now if the cost is low then you can make more vs if it was high.  now the  bases can  only allow 1 1/2 unit to be build at a time because of structure of economy is set up in this game. The penalty of only to be units that can be made out main building is not really a penalty but this is not a penalty since all units have to follow this rule ( exect cutter can have 7 supply pads with 2 elphants that is only exception.)

 supply pad rate (spr) / rate per seconds (rps)  = max unit rate (mur)  The only way to stop the spam is to effect the rps and the only way you effect is increasing its cost or decreasing its build time.  but since its strength based on the build time then you need to nerf the % health and damage to equal its new build time.