How to Make Heimerdinger Viable again.
Heimerdinger is an interesting champion, suffering from a major problem, even after his rework....his turrets are garbage. sure they can seem super broken in solo que, but only if you don't know how to deal with them. If you suck and ignore them and just try to dive heimer under them you gonna wind up dead. But in a 1v1 against heimer anyone worth there summoner lvl will just keep picking off the turrets until he runs out, blowing a bunch of hiemer's mana and time. and in team fight situations they are almost totally useless, because they will either be too far away to make a difference, or you will die trying to place them close enough to be any good and in both cases the turrets are likely to die from collateral damage almost instantly and have 0 impact on a fight.
But if left alone they can be devistating, a simple damage or health buff is not going to be enough to make heimer viable. They need to be given some new utility, a good place to look is the shaco box. shaco boxes while point for point are less powerfull there utility makes them extremely useful, the combination of the stealth, undamageable state they enter to the fear that will guarantee the box will at least do some damage before it dies. these features allow for strategic use and placement that heimers turrets can never hope to match.
That said just copying shacos boxes wouldn't solve the issue either, heimers turrets need a something different to work with the heimerdinger style. I suggest that heimers turrets gain a mini version of Braums unbreakable that will rotate around the turret to block based on where heimerdinger is relative to the turret, allowing the turret to be used as a sheild for heimer to hide behind to give him a tool to deal with all the champions that counter hiemer by having "skill shot" that hit everything in there path like TF wild cards etc. adding this to the turrets combine with a substantial health buff would make the turrets a worth while investment, balancing out the fact they are completely immobile and there for super easy to target and eliminate without taking any damage from them at all. this will also lead to much more intersting gameplay, allowing heimer to fill the roll of the TF2 engineer, making a home away from home where hiemer and his teammates can use to regroup before making a push.