Never been an Urgot player, so not sure if my opinion is terribly valuable, but I think Urgot is quite conceptually unique, and think he's really ripe for a Sion-level heavy-duty rework.
I've heard people talk about how his ult is awkward on a marksman, and how he should either be switched to a true marksman or a true tank. I think that seems like the cowardly approach, as a tanky marksman is still a very cool (if difficult) space for a weirdo champ to occupy. So that's the core of what I would want to keep on Urgot, even at the expense of maybe his most iconic ability: his homing acid hunters. Since as far as I can tell, the acid hunters end up functioning like an extra, heavy-duty AA anyway, I'd rather just load that power onto his AAs themselves. Instead, I'd play with giving him variable mobility and tankiness, pushing him slightly into the space of a Starcraft siege tank (but without the extreme range), where his playstyle would be about getting into an optimal position where he can turtle in and blast away, splitting up the enemy team in the process.
My hastily thought out new kit follows - all numbers are very vague guesses:
Basic AA - still quite short range (close to live) and high base damage
Passive - probably changed, but not sure. Considering something where he gains penetration scaling from his resistances, to encourage building some tank on him?
W - (most kit-defining ability, so it comes first) A toggle ability with a 8-10s CD after deactivation. Applies an 80% self slow and short channel (.3-5s) to turn on or off. Gains a shield like current W, about 200 range, and significant attack speed bonus (maybe degrading over time/with movement). Now has to choose whether to be super immobile heavy-duty marksman who can soak some damage, or more mobile short-range form.
Q - (most radical change) - some kind of short range charge/dash/leap. What?? A mobility tool/gap-closer on Urgot? Sacrilege! But yes. Fits with his kooky crab-leg design, and his thematic space of terrifying Noxian executioner. Lets him escape/maneuver if necessary (not sure about crossing walls), and dive into enemy champs. If it hits a champ, applies a damage debuff in a small area for a couple of seconds. This means his needs to commit to attacks to gain his old passive's dueling power instead of just kiting and being a general POS.
If W is active, dash is replaced by something else... maybe a short-range cone CC or displacement effect. Not sure what would synergize best.
E - Thinking something sort of similar to current E, but longer range and with a delay. Maybe a very heavy slow on a direct hit. The idea of this is to complement the shortcomings of the Q/W playstyle, allowing some poke/catch potential at longer range while trying to set up for the engage opportunity. Could also include a shorter range area damage/debuff when W is active, for more of a teamfight impact combo.
R- Basically the same switcheroo as now. Not sure if the fear effect needs to be kept - could be cool, could be overloaded. W can be activated during R channel, causing it activate (with shield) on arrival.
So, pretty different from current version, but I think something along these lines could be a very cool champ fantasy of a tough, tactical, terrifying, technological ranged butcher. With crab legs. Curious to know what people think, though I expect any actual Urgot players are severely triggered at the thought of losing current Q/E. Be kind plx!