Both offices held enormous powers, however were meant to be exercised only in case of extraordinary circumstances. While the Dictators had a term limit, a lot of times it was ignored, as in case of Julius Caesar. Reelection in Weimar was not limited however. The political powers of both offices led to their respective republics becoming de facto monarchies, one with Augustus and the other with Hitler as heads of state with absolute power. So I am interested, whether or not it is legit to say that Weimar Republic's collapse resembles the collapse of the Roman Republic? I do know that the office of the Dictator is not the only reason why Roman Republic collapsed and that the fall of it had started before Caesar was even born, but Caesar did contribute to its fall.
Whoa whoa whoa. Slow down a bit. I don't know very much about the Weimar Republic, but we should be very, very careful about equating Caesar's dictatorship with the office of dictatorship in general. Caesar's dictatorship(s)--he held three--were nothing like the office of the dictatorship previously. For one thing, the dictatorship did not legally exist anymore during Caesar's lifetime. While the dictatorship was not formally outlawed until the passage of the Lex Antonia in April of 44, it had lapsed by Caesar's lifetime, with the last dictatorship having been held in 202. The New Pauly notes that after 202 the office was replaced by a "prodictator," who mostly assisted in internal matters like helping police the public assemblies. But the actual office of the dicatorship held a sort of fuzzy status as being a quasi-illegal office--as I recall there was a senatus consultum against it, but I'd have to check. Neither Sulla's nor Caesar's dictatorships should be considered a continuation of the old office. For one thing, neither Sulla's nor Caesar's three dictatorships were bound legally by any time limit, whereas an actual dictatorship was. This time limit was not often ignored, as you claim--in point of fact that time limit on the dicatorship was never ignored, since neither Caesar nor Sulla's extraordinary magistracies bearing the same name had time limits.
I'm really going to hammer home that the dicatorship was not the same thing as the office that Sulla and Caesar held. It just had the same name. The traditional dictatorship was a senatorially-appointed (or, rather, senatorially-approved--technically any magistrate could nominate a dictator or any other extraordinary magistrate, the senate just had to approve it) extraordinary magistrate with clearly-defined legal boundaries. He was bound to a service of a maximum of six months, and despite what later Roman tradition held, it's quite clear from Livy that the dictator was not, as the OCD notes, exempt from either tribunate veto or popular appeal (provocatio). In fact, the dictator had quite a lot of rules--he had to ask for permission from his magister equitum, for example, before he could ride a horse, and he was not exempt from prosecution after his term of office. Caesar and Sulla were bound by none of these restrictions, and their magistracies should not be considered the same as the traditional dictatorship. Indeed, their magistracies weren't considered the same in antiquity--while an actual dictator was senatorially-approved and did not have a stated goal of his magistracy, both Caesar and Sulla were confirmed in their dictatorships by the passage of laws in the comitia and their magistracies were formally bound to a purpose, the reorganization of the constitution.
Not really an answer to your question, I'm afraid, but I really do want to make it quite clear that the extraordinary magistracy that Caesar held is very much not the same thing that lapsed in 202