Because I am not very good in melee fight in DS, in all three games I played a sorcerer starting from sorcerer origin. Curiously, starting from the same premise all three sorcerers ended up in very different way.
(All these characters are PvE characters, obviously)
In DS1 the character is as pure sorcerer as they can be. Lightest armour (Crimson set with Crown of Dusk), Grass Crest shield and catalyst. Long robes, weird hat and a wand. I had a enchanted-stated sword but I cannot recall the situation when I had to seriously rely on it: mostly it was used to finish almost-dead enemies and don't waste spells, or deal with dogs. Most used spells by endgame are (Crystal) Soul Spear and (Crystal) Homing Soulmass; Fall Control and Hidden Body for utilities. Heavy reliance on a Ring of Fog later and a bit of reliance of a bow to snipe or draw enemies from afar before that.
In DS1 the sorcery is pretty much built-in easy mode. Lock-on range (required for sorceries) was sufficiently long not to trigger most of enemies before the first strike, and enemies didn't have much of magic resistance - thus each spell dealt good damage, enough to one- or two-shot most of the common enemies. With tougher enemies it was hidden body and run around, or targeting them from where they cannot reach me. Spells in DS1 also have no stamina cost, therefore while going through the level it was enough to just cast-withdraw-cast-block-cast. As long as the encumbrance is light and attunement is plentiful, it is mostly enough just to lock on and wave a wand. With Ring of Fog (so not to waste spell slot for Hidden Body and ring slot for Lingering Dragoncrest ring) everything became very easy: enemies only got alerted from a very close range and usually one by one, therefore most of them were already dead by the time when they thought of coming closer.
In DS2 (which I played the last of all three games, starting with SotFS edition and later going through original version) the character is master of pretty much all kinds of magic while still looking mostly like a mage - light armour (Lion Mage set with Hexer hood), Sunset/Sorcerer staff, Dragleic Shield. Aesthetics of attire gave a very vagabond/exotic look (not that many classical wizards wear a collar with chains and show a bare midriff and legs). Because of the all changes to magic in DS2, the character relied quite heavily on a bow and fire sword (the same fire sword I found in a fire cave that I kept using pretty much until the end). Most used spells are Dark Orb, Great Heavy Soul Arrow, with Yearn and Caressing Prayer for utility.
With DS2 developers obviously took care to make sorcery more challenging mode to play and I am happy that I played this game the last, after a power trip that was DS3, and thus was both more familiar with melee and could take my time, because otherwise the sorcery is frustrating more than it should be. Not by itself, so much as by combination of multiple overall changes to the game – enemies in bigger groups, slower estus recovery, more NPC invasions, initial casting speed being slow, agility problems, lack of initial good shield. Lock-on range for sorceries is also mostly shorter than aggro range of enemies, denying the first strike, and with DS2 enemies tending to come in big groups and mostly having sufficient resistance to magic (or maybe just base damage for spells being lower), sorcery alone was not enough alone to power through. I had to rely on bow and sword more than I wanted; whenever I could safely snipe I would safely snipe. Switch to hexes was just a matter of practicality: Dark Orb is more plentiful than Soul Arrows, deals better damage with proper staff and also have a slight knockback effect, which is sometimes all that stands between being or not being horribly murdered. Lack of Ring of Fog, multiple enemies and tweaks to casting speed made it all about making a character as much of a fast-casting turret as possible, backing off and casting, casting, casting then running away and waiting for AI to reset when it wasn't enough.
In DS3 (which was chronologically my second game) the character ended up wearing Morne Set with Crown of Dusk, heavier shield and weaving Moonlight Greatsword around like a weird fighter-mage they become. I think the shift started around Deacons of the Deep, which are much easier to handle even with underpowered broadsword and poor reflexes than with spells (and poor reflexes), or maybe it begun with Wolnir and his bracelets. I know for sure that it fully happened on Aldrich, which was the first boss I had to seriously beat in melee, because he was just too fast for spells. Maybe it is a better game engine, or overall better AI design, but melee wasn't impossible for me anymore in DS3 as it was in DS1 and later in DS2. Good sword asked for good armour, and somehow I ended up a kind of sorcerer with sorcery as a support tool, not a main means of progress. Most used spells became Pestilent Mist, Great Soul Arrow, Crystal Soul Spear and Hidden Body.
Hidden Body is back! (or, chronologically for me, it didn't yet leave). Combined with DS1-like lock-on ranges longer than aggression ranges it means mostly the same thing as with DS1 - cast Hidden Body/cast/cast or, on many occasions, Hidden Body and cast/slash/slash. Pestilent Mist is a new ring of Fog, meaning that when cast from under Hidden Body, it doesn't trigger enemy aggression at all, so for tougher enemies, whom I still couldn't handle with melee, it was mostly poisoning them from afar - two PMs were usually enough to take down even Ringed City and Harold knights. Heavier armour put the character into medium encumbrance but mechanics for it were much more forgiving than in DS1. Changed mechanics of attunement and focus points meant that I didn't have to learn multiple versions of the same spell (from DnD point of view it made me a spontaneous caster, not Vance-memorization caster) and could use souls to level up strength instead.
To add, that in all three games I had a fully updated pyromancy flame with quite a few pyro spells but never got the timing right, so, aside of very occasional Flash Sweat, never used it.
Strangely, despite DS3 having the most comfortable magic and manliest aesthetics of being in Morne armour with big glowing sword, it was DS2 which I liked the most from the magic point of view because it really felt like a world where a mage had to desperately scavenge all available magic, rely on all available tools and make compromises with themselves (as I didn't want to learn hexes, but without them the game was an even bigger pain) in order to reach their goal.