How do I stats and do I need to cross class?

[LDR]

as others have mentioned, changes are being made to tanks in 3.2 on Feb 23rd. VIT will become the main damage stat for tanks rather than STR so it will probably be best to gear and stat towards the 3.2 changes rather than go with the current STR meta.

as for cross classes, Provoke from GLD at level 22 is a must. at level 34 GLD gives awareness, many many tanks will recommend you have this skill also.
it will also be worth your time to level Pugilist to 12 for Internal Release, WAR loves this skill and 12 levels wont take much time.

DRK shares skills with MRD/GLD so if you can suffer getting GLD to 34 and then do the rest of the game on MRD/WAR you will have everything you will ever need.

as for how it plays, it has elements of both but also its own unique flavour.
you really need to try it to know!