Phil, you need some myths dispelled about the game.
First, the resurrection scrolls are there for a reason. Sometimes you make a mistake or something random happens in combat that you can't predict or stop. This results in a character getting killed. Even the best players occasionally get a character killed. Also, in your first play through, there are DEFINITELY things you will encounter for the first time that will wipe most if not all of your party. No spoilers other than, it will happen. Getting a character killed and using a resurrection scroll is not something to be ashamed of. For that matter, most of the consumables in the game are there for a reason. Use them if you need them.
Second, gear matters. If you are running into difficulty, update your old gear. As a general rule, the gray gear is cheap and should be kept at the level of your character. Green gear can be at level or 1 level below your character's level. Blue gear 1-2 levels below, purples and unique gear can often be useful for 3-4 levels. However, if something is more than 4-5 levels below your characters level, it needs to be replaced.
Third, party composition matters. If you have one character burning opponents and another trying to freeze them, you likely won't accomplish much. Three things that you should have on two characters (not the same two, spread the responsibility around the party) is magic armor replenish , physical armor replenish and healing. It is OK to have a healer in the group that covers all three. If you do that, try to have a separate character be the back up character for each of the other three.
Forth, D:OS2 is an open world game. That means you are entirely capable of stumbling into areas way above your character level. Fort Joy mitigates this to a point, Driftwood does not. Be sure to check the levels of the combats you are getting into.
Fifth, tactics can be a big part of the game. Take some time at the beginning of a fight and come up with a plan for the party. Some opponents will have very little magic armor, some will have very little physical armor. Plan your the fight so that your group can strip the armor from opponents as quickly as possible so you can begin to crowd control them. Some fights are designed for the player to attack from a specific direction and the opposition has all the advantages if you do. Try to find a different way to start the fight to remove the advantages from your opposition. Examine your opponents. Some opponents will be have high to 100% resistance to certain types of magical attacks. These opponents will have weaknesses to a different element. Try to attack them using the element they are weak to.
Sixth, XP is a factor in the game. While the main quest line does a decent job of forcing enough XP on you to keep your party at a reasonable level, you should do as many side quests as possible to get as much XP as possible. For someone familiar with the game, it can be quite easy to stay ahead of the level the game expects you to be at. However, this involves finding and completing as many side quests as possible. Conversely, if you have not even completed all of the main quest line, you could be under level. The only way to catch up is to do all of the side quests you can find.
Finally, character builds matter. Each character should have one main ability focus, be that Warfare, Summoning, Geomancy, etc. They should have a secondary focus that should have some synergy with the primary focus. Often there are specific spells that will aide a build that are outside the two main ability sets, it is ok to put a point or two into other abilities to pick up these spells. Just remember to keep a main focus.
Any one of the above or multiple of the above could be the reason(s) your are running into trouble. I hope this helps and you can stick to the classic difficulty setting. However, I suspect once you figure out where the problem is, you may find classic becoming too easy. That will give you a reason to do another run with a different party on tactician difficulty.
