I suppose you're right. I used Dunban-Riki-Fiora for that area, at level 93, and managed just fine. The 7th character has a lot of defence, and Dunban is quick enough so that he never gets hit anyway. 

I've been trying to use Reyn a touch more this playthrough, but he still doesn't do it for me. But if you like him, then fine. Not criticising that choice, but if I had to recommend one player to drop, it would be he.

I gotta admit that this is my first time playing a JRPG - and I need help. I've played WRPG and never found them hard to handle... But reading all this you guys are posting just makes me realize how little I know in optimizing my characters! Could you perhaps help me out!? I'm just 6 hours in and only have Shulk and Reyn at the moment (I've entered the Tophra Cave and are making my way to Bionis' knee).

How should I costumize Shulk and Reyn??? THX!

That early on, your options are far more limited than they will be in the future. The good news though is that optimization in this game can be done and undone at pretty much any point, so don't sweat maximizing your characters yet. Any gem, armor, skill link, etc. you put on your character can be changed at the drop of a hat if you want.

The ONLY things you should pay attention to right now is which skill(s) a character has that you want to get sooner rather than later (you'll eventually get them all), and more importantly affinity between your party members, as that permits greater skill linking/chain attacks (and can take quite a while to build up to max!)

I played over 25 hours until I knew how to link chracters. And optimizing the chracters is overrated, give  frequently new Armor and Weapons except shulk, and fight frequently and you´ll be just fine.

Reyne is maybe even the best Character in the game imo. Because of all the reasons you just gave us, and I have to say that I never had a problem with any opponent when I had Reyne in my Team, and he´s not just usefull i pulling attention but in chain attacks as well. When the opponent is knocked down he has this ver powerful atack I don´t know how it´s called on english I mean this red Sword icon, and he has a yellow attack as well. Reyne is like Grunt of Xenoblade I just feal safer with him in my team. The only really useless character is this new girl I tried to fight with her against some stronger enemies and failed.

As far as I'm aware, you're in the Bionis' Head, which isn't even half way through...

The game is easy up until now. Reyn's usefulness drastically decreases in the next few areas as the game throws more enemies of a higher level with spikes etc. dealing heavy damage. 

Melia, and I'm tired of saying this, but she is quite easily amongst the best characters in the game, if you play as her. She can damage Mechon without Shulk, she can deal all sorts of damage (Burn, poison, health-drain etc) to the enemy, and can assist your team (ether, strength up, health recovery, agility up etc.) greatly. In addition, her ether is by far the highest of any character in the game, her ether defence is also the best, her HP, strength and defence are all reasonable as well, and she can easily topple enemies with Starlight Kick, without having to break. She can also chain the easiest of any character, as her Talent Art can be used at almost any time. 

Basically, she's an all-rounder, but excels in Magic attacks. Up until this point, that's not been of much importance, but if you abandon her now you'll find your passage through the rest of the game is much more difficult. Reyn, as a physical attacker, is useless against Ether-based units, like the cloud-balls, for example, and enemies with insane defence come around soon. Guess who's the only real character for those instances?

As I said, all characters strengths and weaknesses etc.

As mentioned above, the fact you haven't finished the game is obvious here. Skill-linking is just as important, if not more so, than constantly improving weapons and armour. If so you can gain the upper-hand, such as Shulk's link to fill the Talent Gauge when there's a vision, or to gain Haste and Tension at the start of the fight, or to increase exp., hit chance and Gold when fighting in the day etc.

Skill links give you far greater oppurtunity than new weapons and armour, and if you 'ignore them' you'll come unstuck.

It's the reason why killing UM's is almost a neccessity, as you gain the ever-valuable affinity coin from it. 

I didn´t say that its unnecesary I only said that I didn´t knew how to do it, and still made it trough. Of course it´s important, to link squadmates together. You link people with one of the girls I don´t know which one, to react stronger on healing, if you link with shulk you have a 5% exp bonus. So yes I´am aware of the importance I just didn´t know how it´s done. Same is for Gem crafting, I crafted my first gem on saturday cause my bag was full.

thanks guys for your opinions! I do, how ever, have two more :P

What's skill linking?? Is that used in the chain attacks?
And should I be thinking about "tanks", "DPS" and that stuff?

Skill linking is the method of linking together specific areas of different character's skill trees. 

You're aware each character has 3 skill trees, right? There's another 2 for each character, but they're avaliable in side-quests (and are actually the best). The 4th skill tree requires a quest-chain to be completed, and a specific affinity for each area. The 5th skill tree requires the 4th skill tree and the completion of the game up until a certain point. These extra skill trees are INCREDIBLY useful, but I'll save that for later. 

When you find a landmark, or finish a battle, you gain exp. (levelling), AP (Art levelling) and SP (Skills). After a certain amount of SP is received, denoted by a small yellow bar underneath the exp. bar on the battle screen, you'll gain a skill. Different characters have different skills, so Reyn is more attacking, Shulk is mainly Monado etc. 

When you reach a higher affinity between characters, you can skill-link, or 'create' your own skill tree from different characters. If their affinity (seen by clicking in the centre of the affinity tree) is yellow, you have 1 chance. Green, 2 different slots etc. You can link any unlocked skill from this character provided that the character has unlocked that skill, you have sufficent Affinity Coins (1 for each level and UM kill) and it's the same shape (circle, square etc, diamonds can never be linked). Then both characters will have that skill. So if you want all characters to wear heavy armour, you'll need to link it with Reyn's skill, for example. You can easily change linked skills by simply selecting them. 

As for the tanks, where are you in the story? If it's early on (before Makna) then I wouldn't worry, as you have too few characters to bother. ut if youre later than that point with 6 or more characters, then maybe you should think about it...