AA maintanace and

I recently took a multi stop business trip to the US. My route was LHR-ORD-SAN-DFW-CHA-CLT-LHR and as I found AA serviced all my required stops I decided to go with them, making one booking. During this week long trip I experienced a couple of delays – ORD-SAN = leaking water from forward toilet (2 hours) and DFW-CHA engien issues (4 hours). Thought I was unlucky until I read this

http://www.ibtimes.co.uk/american-airlines-plane-forced-make-emergency-landing-after-fuel-found-leaking-out-wing-1528489

So does AA have a poor maintenance record?

Also during my trip I arrived with a colleague at CHA early enough to try and get the earlier flight to CLT. Travelling on a business class ticket and having Sapphire OneWorld status I thought it would be easy. I was wrong – as I had booked a single ticket for my entire journey, I could not be change to the earlier flight as I had an “international” ticket – I explained I was trying to get to CLT from CHA so there was no international routing involved. I was again informed that I could not do it, even if I had offered to pay. My colleague left on the earlier flight (he originally booked that flight) and later told me there were 2 empty seats on board. Is this normal airline policy or just AA? I normally fly SkyTeam and being a Platinum member have never experience such a problem, although Delta did ask for a $25 fee to change.

On my return I complained to AA via their very unfriendly online system and they credited my account with 7500 miles – not sure if that is worth anything!!

Is my experience a one off or do others often have such issues with AA? Thanks.