My advice would be to first spend some time at the Genius bar and ask them to show you how the keys work. Don't worry about the past for this appointment and focus on the problem you have now. You can then relate the past experience with the tech towards the end of the conversation to see how normal your experience is.
With the millions of devices out there, if there were truly a design issue, there would be a line out the door and around the block with people needing service.
It's entirely possible you just had bad luck or are getting some small debris under the keys. Even a pet hair in the right place can disrupt the exacting tolerances needed for the scissors to work if you pay attention to thinks like initial force to press and final force to press or compare one device to another side by side and study the key action with care.
Once a technician shows you the underside of the keys and perhaps your T key the cause of the odd pressure to activate should be clear to everyone.
In this case, you will see there is one spring that encases the key's electrical contact, four plastic to metal pin joints and two plastic to plastic pin joints. For the larger keys like the option, return or space bar there are additional metal struts plus larger and/or more than one scissor mechanism.
As with many things Apple, the devil is in the details and the details here are quite fine.
