And why do you think it would be a good idea?
No reason to go for lights does NOT promote infantry focus, it promotes medium rush, because you want to get an edge over opponent at best.
At worse, it promotes strats like volks or maxim spam even more, there is also an economical aspect, where UKF and USF simply can NOT commit more to infantry then they do now as it breaks completely their menpower economy.
I don't think there is anything wrong with game pace right now, pretty much all armies can focus on the infantry more in early game to a point, but making lights less attractive will achieve nothing but med armor rush.
And last but not least, without lights, USF is fucked up, UKF is fucked up, OKW is stripped from at least 2 BOs and soviets that don't spam maxims are so fucked up that its not even funny.
If someone is struggling vs lights, then perhaps it would be a good idea to anticipate and get some AT out.
More side tech would add reasons not to go lights that doesn't encourage faster mediums.
USF could have another Barracks upgrade for 25 fuel(maybe unlocks a buffed volley fire and a new assault fire ability, or something) and OKW could use sideupgrades and even T0 upgrades for economy would be neat. (Defensive tactics upgrade, maybe field craft, things like that.)
Soviets grenade/molo could be folded into one 35 fuel upgrade, and given another upgrade (cheaper con reinforcement for 45 fuel maybe) and Ost/UKF don't need anymore