A post for clarification:
The current status of the shield of the Titan is very much intended. Their strength is supposed to be speed and a shield that allows you to take short engagements, kill lower-tech units then kite away while not losing HP. This is by design and is supposed to reward good micro and using your units to their strengths. On the other hand, Harb is a hybrid between a raiding unit and a frontline tank. It has more HP, more DPS, and absolutely wrecks Titans mass for mass in a direct engagement. Both of these units have their strengths and weaknesses. You can't just take 2 stats and compare them to each other. You need to not only take into account the whole units but whole unit rosters (need to think how the "power budget" is distributed among the faction's unit roster. Eg. how strong Percy is, and how strong Snipers are). Even if unit A is a bit weaker than unit B perhaps the faction that has unit A also has unit C that is stronger than its counterpart. As long as units serve their specific purpose then there is no reason to make all units equally good.