Re: (Nutaku) Milenium War Aigis (English Version)
@Altrius,
Mission maps can be beaten with a single team formed from the start.
There's typically a base or "core" everyone starts with and branches out from there, but most teams regardless of access to units will have the following:
2 Soldiers
2 Archers
2 Healers
2 Mages
The above is universal (almost always), and even where some maps have a gimmick, it's still a good idea to have the above in the team unless it is just one of those challenge maps that out right require specific unit(s) types to get past.
As for some of the gimmick maps differences, some are as simple as placing an archer before the soldier. There are several rush maps like this, that placing the archer first instead of the soldier is more ideal in preventing being overrun. However the above core is based on current maps we have and availability of those units ensures a prominent core that everyone uses, even now.
It's also the reason you find all recommendations for CC often go to Katie (soldier) 1st and 1 of the two archers as the most recommended units to CC second, since everyone has access to them. The healers and mages often follow. Witches are not actually on the list, but given that we get 2 for free, most teams have two for quite awhile till they can either get a replacement witch, or another unit that fits their play style.
Currently the biggest variable you can see when looking at most players teams are what duelists they use (Valkyrie, Rogue, Princess) and if they use 1 or more HA's and / or Witches. Typically this is the only wiggle room we see in many players teams, and also the most diverse portion of a given team. Because of the core, they are often successful regardless of the non-core units, provided they are leveled enough for the content they are trying to beat.
Sorry if I wasn't clear about what I was saying either. As I said before I'm not arguing about the strategic value of building up all units, or just swapping units out as needed, as there are some maps that simply can't be done with anyone's typical "blind run" team, they are however, at least currently, few and far between. So my statement of the core team being the first things that should be worked on will hold true.
(In general)
Most players will need to level their core units, even replacing as new units are acquired ( gold for a silver healer for example ). For the most part having that well rounded team with multiple options will serve them better then trying to just pick and swap units randomly or with out good cause.
Another thing is the way maps limit placement. So it's also recommended to split your team between melee / ranged units. You don't ever want to have just two proximity units in a primary team and the rest ranged, or vice versa. That is a strategic flaw, and will cause many failures (wasted Cha and/or Sta). Having 7 of both and then adding a final to finish out the team will be the most productive especially for new players. This way you are neither lacking on ranged units, nor melee. You can of course replace units at a later time to fill any needs, but doing the above will get you further with less, and with less "I need to level X (non-primary team) unit cause I can't pass the current map" situations.
Just how I've done both my accounts, and both have been successful. My free account has done very well because it has a good core, and a swath of non-core units to fill various needs. The only thing I really desire for that account is access to a princess, which I don't have, and likely wont have access to unless I get lucky in 2k gatcha.
Hope this helps people and is more clear then previous post.