If you're getting mana burned you're either cced or not dodging out of los of the priest properly. The first you can't do much about but the latter should be easy to reduce. Just make sure you're always in a position where you can get out of los.
Likewise with warriors - if you stay out of los as much as possible they'll find it harder to charge you which means they get less pressure. Warriors are hard work though, get the feral to chain cyclone on the warrior when you need a break and use your 4 piece to escape away whenever the warrior is snared.
Playing KFC ask for buffs from hunter from his pet. You need resil to survive a lot of teams, however remember that inner focus makes you immune to interrupts for 4 secs so use it when their cooldowns are available and you believe interrupts are commin. Use mod- interrupt bar. some buffs from hunter pet is immune to being crit and freedom.
I played the same comp Priest feral to 2k++, heres some tips for warriors. First off, you are not supposed to be able to survive a warrior for very long left alone, you WILL die. The key is peels from your partener....he should be keeping cyclone and roots up on the warrior whenever possible. For the times that you ARE on your own you want to use your shield at the right times for the freedom from movement impairing effects, and try to space out your defensive cd's as much as possible. For example, I keep up renew and Prayer of mending at all times...when i start to dip to about 60% i will desperate prayer and run around, try to LoS, Ill use pain sup in another pinch...and try to go as long as i can before having to use power word barrier....now desperate prayer is getting close to coming off cd. Always use inner focus off cd.
The Key in both 2s and 3s is communicating with your team to get peels when needed and to cc the dps and/or person mana burning you.
If a DK is stacking necrotic strike on you he needs to peeled so you can recover, if a rogue is shadow dancing on you and you are under a lot of pressure call out for help. Also juking will help you a lot, baiting their interupts so that you can then free cast.
If I want to make SURE I can cast, I will mind control the DK...he HAS to interrupt it or I can walk him across the map and heal to full, and even when he does mind freeze it I can still free cast. Its 3am and i dont know if im making any sense lol so anyways....
Hope this helps a lil bit and wish you the best!
Yes, sounds like you are doing everything right..... what will help you out a lot when fighting warrior priest, is to dispell the priest as much as possible, dont spam it if he has no buffs, but try to keep his shield, renew and Prayer of Mending off...this will force him to cast which your druid can interrupt him for a lockout to build up some pressure. Playing with a feral is a balancing act of knowing when and how to play offensively to help land the kill. ALso if you know the warrior used his trinket and is about to go into a full cyclone, use power unfusion and try to get in 2 or 3 burns on the priest.....you should time this with the druids stun to make it easier Dispelling certain things off enemy teams can dramatically change the balance of the game...for example, if you are fighting a mirror and you always dispel the ferals predatory swiftness buff, you are eliminating a huge portion of their cc.
For warriors, what i have found really helps is a Range Finder addon, and making sure you stay in the 5-8 range away from the warrior. This is the range where the only thing they can do to hit you is Thunderclap (lol) and Piercing Howl. If they are snared too the piercing howl helps that you don't accidentally get into charge range.