A lobbyist is really a salesman representing an idea. A good idea deserves a hearing. Too many good ideas do not really get a fair hearing and we all lose when that is the case.
Your political representative uses or should use your geography as their base of concern. Most jurisdictions are based on geography whether elected or bureaucratic and we do share concerns (special interests) with our neighbours. In addition to your narrow concerns you should be concerned about the rest of the world, because whether you understand it or not it is all inter-related to what you do value.
Each special interest needs advocates or they will not achieve proper attention. An elected representative cannot be an expert in all the fields that affect their constituents. There are many new and/or unknown issues and opportunities that should be advocated. It takes a lot of effort to get a new idea adopted that can benefit a wider audience. A good lobbyist (salesperson) is responsible for progress. The elected politician needs to analyze the factors of any issue and make a logical fair decision. Sometimes they do not calculate right and in other times they give more weight to one side perhaps because they are rewarded for doing so.
The bad image is deserved to the extent that a lobbyist has disproportionate influence. This usually comes from money but sometimes from traditions that have an overdue grip on us. Money creates a problem because it can sway decisions that affect people who don't have more than a vote once every few years to affect that decision. In most modern democracies it takes money to get elected, lots of it. A politician needs money to draw attention to themselves, to find out what the voters will vote for and to present themselves most favorably.
The more successful lobbyists seem to give big donations to political parties and candidates. No one likes to say the donations affect any outcomes, but they certainly seem to open up access.
It has come to the point that most politicians spend much more of their time fundraising than they used to. This of course dips into the time needed to actually serve their constituents. They need to study issues from all angles, they need to discuss with others to better understand reasonable compromises. Political donations come with a price. At the very least that price includes time away from their real duties.
To get elected is much more complicated than having the best policies that benefit the most people. There are so many different issues that when narrowing your vote down to only two choices (theoretically more in many jurisdictions) how the policies are packaged and presented is critical. Of course there are the general categories of conservative and liberal, but that doesn't always work for most of us). As one general example none of us really want to pay taxes, but we all expect as much service as possible.
The ideal is to have a level field for an election. Admittedly that Utopian ideal is inconceivable when you think hard on the matter. But we need to work towards it and a big factor is tied to money. Why should it take a colossal amount of money to get elected? Why can't candidates be given an equal platform to present and debate their policies? One problem I admit is that the voters are not all committed to making an open minded effort to evaluate all the different issues that impact on their society. Politicians of course know this and try to use all the resources they can command to get their message out to voters in such a way a prospective voter will feel an emotional resonance. Un- fortunately politicians have learned that negative messages about their opponents can also influence the results. Distortions are all too common. Politicians avoid being pinned down--personally I sympathize with that, but they should be able to convey their general philosophy and run on some kind of a track record.
Money requirements are supposed to eliminate frivolous candidates, but it also eliminates many earnest competent people. I would add that before someone is eligible for the higher offices, they should have some experiences at lower offices. This is not intended to eliminate successful people from other fields, but force them to gain some government experience before given a chance to manage at a higher post.
For a level election it is obvious to me that each candidate should have equal access to the voters. We could put resources to better use by avoiding ad wars. Only individuals should be allowed to contribute small amounts. An elected official cannot really be forced to listen to everyone, but at least voters should have the option to vote for someone else. A smart politician will listen to everyone--even those they do not agree with or whose association would be criticized. What a politician can accept from a lobbyist should be very strictly limited.
A big loser in my proposal would be the media. There might be a slight shaking out and rationalization of how they use their resources to attract an audience.
Lobbyists should be registered and their salaries made public (maybe including their expenses). There should be no shame in their success as long as based on merits. There are at least two sides to every story and you have to give some credit to the person who presents their case more effectively. If you happen to be on the other side you need to find a more effective way of presenting your case. What distorts this procedure is bribery.
Bribery might be difficult to pin down and one can be sure efforts will be made to bend the rules. As a salesman I understand the benefits of giving someone a sample to test. If something is expensive the test should not include ownership. A lot of room for interpretation, but the start towards true democracy is to diminish the role of money, not the honest function of a lobbyist
An excellent movie that illustrates the problem lobbyists is "Miss Sloane." http://www.therealjohndavidson.com/2017/09/miss-sloan-under-rated-movie.html