While I and others have picked up on the effectiveness and implementation of towers as they are at present, here's a summary of issues with towers from my perspective:
- Hero abilities affecting buildings -
I mentioned this in my first impressions post, and it's probably the most major problem with towers for me at the moment. The fact that abilities can affect towers makes them extremely easy to take down. With the Torch Bearer, for example, you can simply freeze a tower, stay out of range of any other adjacent towers and solo it yourself. This is most effective when you get reduced cooldowns (for chain freezing).
In a game yesterday at around level 12 I managed to solo one of the mines by myself by using this method. Granted, you don't always get this opportunity when opposition heroes come down to defend, but in any case it should simply not be this easy to take down towers. In DotA (stop groaning) abilities do not affect towers so you would not be able to exploit them in this manner.
Even in the early game where soloing is risky, freezing towers allows your creeps to attack them with much more freedom.
- Range too low -
Tower range needs to be upped a touch. As Regulus you can sit out of range and snipe them to your heart's content. Increasing range would mean that firstly, it is no longer possible to simply pick them off from afar, and secondly that you will need to wait for creep waves to begin attacking before beginning yourself.
In DotA, the tower range is implemented in a way that means you cannot sit out of range and take them down with your auto-attack - if you go in on your own, the tower will be able to hit you. However, if you wait and attack only after your creeps have engaged, the tower will not attack you until you are clearly the main damage dealer. This means that you have to rubber-band in and out of range, taking opportunities to attackand falling back when the tower has designated you as the main threat and moved focus from the creeps.
- Damage too low -
When a tower attacks you, you really need to feel it. While towers do a relatively acceptable amount of damage in the early stages at the moment, their damage output pales much too quickly as the game progresses.
If a hero is chasing you and you head for the safety of a tower, the chasing hero should really be made to think twice about their pursuit due to the consequences of going within firing range of it. At present, towers neither exhibit this element of safety for allies, nor danger for enemies.
- Graphical size needs increasing -
This has been picked up upon in a couple of other threads, but towers are tiny at the moment. They should be dominating structures on the battlefield.