To get full protection against all kinds of debuffs/CC you need to cast it like 5 times, it's only castable on yourself. Doom and Malison stack, Doom is also instant cast. Clerics get Animate Dead a lot earlier and cast it as a mere slvl 3 instgead of slvl 5 spell, Improved Haste and Righteous Magic stack, No potion replicates Heal. Dragon Breath is a HLA and therefore an invalid comparison to Firestorm, Deva is better than Planetar. Natures Beauty is one of the best CC spells in the game. Then there is turn undead, which makes many undead heavy areas cakewalk and it costs nothing.
Again, game without mods in it's original state is soloable by a beastmaster, so it pretty much doesn't matter at all whom you bring.
In what ways is a deva better than a planetar? You're getting things confused. Yes, getting the warrior skeletons earlier and as a level 3 spell is better. But hey, let's not only focus on the (few) good cleric spells. We also need to look at it the other way around. Now you tell me how clerics make up for the following:
Magic Missile, Chromatic Orb, Spook, Blur, Glitterdust, Invis, Web, Mirror Image, Haste, Skull Trap, Flame Arrow, Minute Meteors, Emotion, Farsight, Fireshield, Malison, Improved Invis, Minor Globe, Minor Sequencer, Stoneskin, Teleport Field, Breach, Clowdkill, Feeblemind, Lower Resistance, Spell Immunity, Sunfire, Contingiency, Death Spell, Death Fog, Globe, Improved haste, Mislead, Pierce Magic, Pro magic Energy, Pro Magical Weapons, Nishruu, Delayed Blast Fireball, Limited Wish, Finger of Death, Mass Invis, Mordenkainens Sword, Project Image, Sequencer, Hakeashar, Abi Dhlazims, Incendiary Cloud, Maze, pierce Shield, PW:blind, Simulacrum, Spelltrigger, Chain Contingiency, PW:Kill, Wail, Time Stop, Shapechange, Spell Trap, Spellstrike and Wish.