Note that if there were to be a weapon weight system, there will need to be major balance changes made. People in general don't like such dramatic changes. It's a high risk to aim for such huge changes that will affect the entire gun tier list.
Cloyd made an attempt to balance guns and the balancing ended up unfinished which is a bit hard to explain. This severely damaged the balancing. Thank goodness Meph and other admins patched up the damaged tier list.
The current guns in era are near balanced. Not perfect balancing but was better than the previous generation of iEra. (The introduction of pay 2 win) Shipka was dreadfully powerful and overused. Has a freeze rate of pistols before. Very unbalanced stats.