I buy one way tix on SWA so that if the price of one leg goes down I can get a credit. With a round trip, if one leg goes down in price and the other goes up, your overall price might not be lower than what you paid so you wouldn't get a credit.
I learned my lesson and will book each leg separately in the future.
I booked round trip for my family of 7 shortly after fares were released, as they were pretty darn good both ways.
When an earlier flight on my outbound dropped in price, I called SWA to walk me through the change. I was assured by the CSR that my return cost wouldn't change. When we were making the flight change the earlier outbound was $5 less than original, but the return had gone up a bit. With a family of 7, even a small difference can add up. She assured me several times that a change to the outbound would not affect the return in any way.
She walked me through the change, as she couldn't do it for me because the new fare was an internet only fare and she wasn't even showing availability at the lower price on the earlier flight. When we got to the screen where it reconciles she said, "you should now have a $35 credit". Nope, the total was still the same.
I was OK with that, as it was worth it for me to pay what I already was going to pay and I got 3 more hours at WDW. SHE was NOT OK with that and put me on hold. After a few back-and-forths and a call by her to a "the home office", they determined that the obscure memo that "just" released earlier that week made my reservation convert to the entire trip being an "internet only" fare, even though the return was originally a different class.
This caused the return to re-price. She REALLY was unhappy with that and did everything she could to get me my $35. Even INSISTED several times that I call Customer Relations to ask for the money. I decided to let it go, as the return fare I was seeing was more than the $35 difference.
Soo.....lesson learned. It could have been worse.
I'm thinking that if lower fares are going fast, you could actually lose out on the good fare on your return if you take the time to finalize your outbound transaction. That is, if both directions are showing a nice fare. But in your case, you are not happy with the current return fare, so it might be worth it wait out pricing on the return.