The only problem I've had issues with tanking on a gamepad is selecting distanced mobs that are either ranged attackers or just late stragglers that agro the healer. I normally like using quick select rather than D-pad (cancel, then hit X to target enemy in front of me).
The work-arounds I've developed (but yet to test thoroughly) is to either just rely on virtual mouse mode to target or have a party member mark it with X and use my X target macro to target it (this requires really good trust between party members).
