There are MUCH harder parts of the game coming up:
1. Firstly, you've got a decent party build - ASSUMING that those bishops are two-school rather than four-school. If they're 4-school bishops you're screwed, but if they're 2-school, (covering the various schools between them) then you'll gain access to spells just in time to need them. (2-school bishops are the best casters in the game - they learn almost as fast as pure wizards/alchemists/etc, with much more flexibility, and a really handy auto-identify class skill). Your bard is a great choice - I'd say to give him the cursed beserking sword from the bank (you won't need to upgrade his weapon that way for a LONG time) and work on his melee so that he can handle a flank if necessary, while using his instruments for anything ranged (with a stamina-boosting item or two he can spam instruments every fight and recover by the next one - just keep spamming the sleep/snare stuff mostly, or silence for casters, or the AoE damage instrument for the low-hp mass-numbers monsters.
2. Use your back-up casters (any rangers, Vi, samurai, bards etc) to be your buff-casters and maintain your buffs at ALL TIMES - firstly because you never know when you'll need them, but secondly because there's no penalty for having them cast the buff and it's the best way for keeping their spell progression going given that you'll need to also focus on other skills during level-ups (the 2-school bishops will have good enough progression anyway, from class bonuses, level-ups and being the main casters during combat).
3. IMPORTANT - boost your bard's traps and open locks abilities (his thieving stuff) over time so that you can make Myles obsolete. From memory he won't go everywhere in the game, and you'll need another option - and your bard can easily cover that. Usually I don't even bother with a thief - I just use a bard for traps and locks, and later I'll use the robot ninja for stealth. You WILL want to sub Myles out recruit a certain robot ninja in to the party, while using the bard for opening locks and detecting traps (and despite Myles' backstabs, a bard with a good sword - like the cursed beserking sword in the bank - is a far better backup fighter, easily holding down a flank while firing off songs.
Now why am I giving instructions on how to make the game even easier when you are complaining about how easy it is?
Because the game gets MUCH harder as you go on.
MUCH MUCH harder.
Firstly, there's the good old level-scaling. The road to Arnika can be utter death at high levels.
Secondly, there's some of the 'hidden' stuff in Arnika (robbing the bank et al) - if you do things right you shouldn't end up in combat, but do it wrong and you're in for a fighjt.
But seriously, don't even THINK about talking about the game benig too easy until you've done the Bayjin area. Have fun with your uber lizardmen fighters getting mind-controlled and slaughtering your own party. Laugh it up as your possessed samurai scores an insta-kill against one of your other party members. Fall off your chair in hilarity as your mind-controlled bard uses his instrument of mass insanity against your party, turning all of them insane, leading to your ninja getting an insta-kill on your fighter, one caster following it up with a mass debuff to your party's armour and the other caster casting mass paralysis on you all.
Fun times
.
The Bayjin are really tough unless you have specifically planned a build around them (party with high mind/spell resistance) - incidentally, it makes iron will a really good 'special' to go for. All the 'specials' are really good, but iron will seems weaker than it is until you get to that area.
The Rapax can be tough, but only until you know what you're dealing with - they are basically just hp-spunges with decent melee damage...so use formations intelligently, spam your disabling songs non-stop, use snares intelligently and ping them with ranged weapons, and hopefully they'll be at a more manageable level of HP nby the time you go toe-to-toe. Still, the castle isn't exactly a breeze, taking on the Rapax royalty and all that.
There are also quite a few really really hard optional 'easter egg' fights in the game, that are quite impossible for a party who would ordinarily be entering that region for the first time. Fight the undead in the temple (not in Arnika - in the fields past Trynton on the way to the swamps( and then tell me things are too easy
).