Frankly, in every game, online or offline, I have been always a warrior type. So in BG series. And I am happy with it. I never dualed them since I like the "pure" class much more, not the crossbreeds. I do use the kits though, they give the flexibility.
I have found the Bberserker to be a good class. He has the power to beat things into little chunks, when in Berserk state, he is immune to many high lvl spells. Smack on Holy Might and he is pretty mean. Add on that the Boots of Speed or Haste or Potion of Quickness and tadaa! Mean dude. I haven't really played "solo" as with one char, since that way I miss 2/3rd of the fun of game due to the missed quests. So from that point of view, I have a party. However, I like to keep him in a good shape so I always equip him with the best possible gear combined. If others die, they can be ressed in most cases. If he dies, game is over (which in my eyes is stupid, since the rest of the party is alive and could easily res him in turn). What I mean by "solo" here is that in many cases, if not most, when I know or feel that I am about to get into big fight, I usually leave the party behind in defensive position and go ahead with just my main char. Ah the fights he has had heheh..
I actually am a person who uses magic a little and relies on the strength of arms and weapons. My casters use slings much more then spells, and when they use spells, they in most cases use dispell type of spells to get the protections off of the target, and healing spells. I have had mainly 2 casters in my party - Aerie and Jaheira. From my memorized spells, you would find really very few offensive spells, if any at all. Most are defensive and healing types. I have never seen really the need to go heavy on magic in BG's, the good ole melee and ranged attacks work out quite nicely as well. You just have to have good equipment and keep the main tanks alive.
My main char has some main stats, like STR, DEX, CON at 19, because I brought him over from BG1, where I used the books. I think there are some such books in BG2 too, but guess I have missed them (save the DEX one, but forgot where I got it).. Since I played the game at first through too fast, then now, when I started it again, I imported him again. Definately it has made some things easier due to the bonuses he got from Bhaal's Tears (I did the good way), so he now fights even more. He wasn't maxed out though, just lvl 14, so I will see now how far I can take him. As for all melee and little magic, well, in some cases it's trickier, in some easier. But it's doable and I like it more, rather then mess with these spells and things.
Also I have tried with the rogue type of char, forgot which kit I used, but he was cool. I got his Stealth as high as I could, more then other skills. With good daggers or short swords, with good equipment and Boots of Speed, you can do surprizingly much with a rogue. Backstabbing many if not most foes, set the traps and snares. Boots will get you out of the harm's way, get away and Hide in Shadows. Cloak of Non-Detection is handy, coupled later with the Cloak of Mirroring, once you get it. Quite fun, I should do it again and stack up on the Potion of Explosions or Potion of Fiery Burning - nothing more fun then to sneak up the ambush set for you, then nuking them and hiding, before they even found out whay hit them. Then backstabbing the rest of the rabble or nuking again. With a good bow and best arrows you can use on top of it, such a char is really something to behold. Imoen was my primary scout char in BG1 you know
. She wrecked real havoc on enemys like this..