Targeting creatures, as I'm sure you are aware, is very troublesome. It relies on the creature's actual mesh for hit detection, which means if it has a fidget animation that signifivantly alters its location (such as ducking, shuffling side to side, kneeling, or even somersaulting!), you can end up wasting many APs on a misclick or even walking into surface and seriously screwing yourself. I'm aware of the tactical view but it's far from being a good solution!
I'd expected this to be better in the EE - sadly it is not. I'm guessing that ship has sailed for DOS, but you must do better for DOS2 at least!
Improvements to targeting are already in the game. Actually, most have been in since the original D:OS release as well. You have several options available to you.
First, obviously, is just left-clicking on the unit you want to attack. If you're in a rush and not taking the time to zoom in on the target first, or don't have a steady aim, then this can lead to accidentally issuing movement orders (which seems to be the problem you're complaining about). So, let's assume this method isn't working well for you and move on.
Your second option is this: when you're using a skill or spell, you don't have to click on the animated creature on the field to apply that skill/spell to them. You can just activate the skill/spell and then click on the portrait of the monster. The UI will highlight the opponent on the field as you mouse over each portrait, providing visual confirmation of your target (likewise, the UI will highlight the portrait of the NPC model you're currently mousing over, removing all of the guesswork). When you have the skill/spell queued and click on the appropriate portrait, the skill/spell will be used on that target in the field.
Now, for normal (non skill/spell) attacks you simply have to right-click on the target model in the field and select "attack" from the context menu that appears. Your character will then initiate a standard attack on that target.
Last but not least, you also have the option of holding down the SHIFT key when left-clicking (which is the default key for placing actions in a queue). Your action will not be initiated until you take your finger off the shift key, and while you have it pressed down you can (at your leisure) verify that you have issued an attack order rather than a movement command. If you see you issued a movement command by mistake, you can right-click (while the shift key is still being held down) and cancel your queued action - no AP used, no accidental movement, no hitting the wrong target.
Using any of those options (other than the first, which is the one you're struggling with) it's simply impossible for you to accidentally move towards your target instead of attacking it. Options out the wazoo, and most of them have been in the game since the original release of D:OS.