I was comparing some of my characters and i have some varied warriors and battlemages / spellsword but my mages all tend to end up using destruction

For a warrior there is one-handed, two-handed & archery. Back in Morrowind we also had spear (technically it was pole arm). Block does some damage but is more of a defence and support rather than a main means of attack. There is also dagger but this is more about stabbing while sneaking rather than a serious weapon to use in melee

One-handed & two-handed can then be divided into sword, axe & blunt / mace.
Archery has bow & crossbow and in Morrowind it had throwing knifes / stars.

Compare the main warrior attacks and compare this to a mage then we only have destruction as the only reliable way to fight off an opponent.

destruction can be divided into fire, ice and shock.

there is close quarter spells effecting the immediate area, there is range and then there is traps.

How do other mages go into combat? Do they also need destruction as a main attack?

Some of the following examples are only possible pre-Skyrim:

"Summon Clannfear 30 Seconds, Invisibility on Self 30 Seconds."

"Frenzy, followed by Summon Atronach."

"Summon Bound Bow."

"Absorb Health on Touch."

"Reflect Damage."

There are a bunch of ways.